PYSEC-2026-3847 HTTPX2: Quadratic SSE line buffering can cause CPU denial of service

Summary HTTPX2's Server-Sent Events SSE parser repeatedly copied and rescanned buffered text when a server split one unterminated line across many response chunks. The total work grows quadratically with the length of the line. An attacker-controlled or compromised SSE endpoint can exploit this...

PYSEC-2026-3933 vLLM: ReDoS via structured_outputs.regex in the lm-format-enforcer backend (no compile timeout) — missed sibling of GHSA-rwxx-mrjm-wc2m

Summary The fix for GHSA-rwxx-mrjm-wc2m "ReDoS via structuredoutputs.regex compiled without timeout" wrapped the regex compile in the xgrammar and outlines backends with compileregexwithtimeout and, for outlines, validateregexisbuildable. The lm-format-enforcer backend was left unguarded: it...

PYSEC-2026-3938 vLLM: Incomplete CVE-2025-62164 remediation can be bypassed by concurrent prompt parts

Executive Summary The follow-up protection for CVE-2025-62164 is incomplete at vLLM revision 26587f9519e22a5c4549ead7595ad9ca3229c4fd. It wraps serialized prompt-embedding reconstruction and dense conversion in torch.sparse.checksparsetensorinvariants, but PyTorch 2.11.0 implements that context...

PYSEC-2026-3837 GitPython: TagReference.create positional reference bypasses kwargs-only --file guard, enabling arbitrary file read (incomplete fix of 3af0c251)

Summary TagReference.create forwards a caller-influenced positional reference value into git tag without it ever being inspected by the unsafe-option guard, allowing an arbitrary file read the file's contents are returned in-band as the annotated tag message. This is an incomplete-fix bypass of...

PYSEC-2026-3871 NLTK: Quadratic CPU Exhaustion in `XMLCorpusView._read_xml_fragment()`

Summary XMLCorpusView.readxmlfragment reads a corpus file in 1 KiB blocks, appending each block to a growing fragment string, then calls VALIDXMLRE.matchfragment on the full accumulated buffer every iteration. Because each iteration rescans the entire accumulated fragment, the total amount of wor...

PYSEC-2026-3869 NLTK: Uncontrolled resource consumption in RecursiveDescentParser via ambiguous or left-recursive grammars

nltk.parse.RecursiveDescentParser and SteppingRecursiveDescentParser enumerate parses top-down with no bound on the number of recursive steps. A small, crafted context-free grammar makes a short input consume unbounded CPU and/or exhaust the Python recursion stack, pinning a process indefinitely ...

PYSEC-2026-3912 pypdf: Inefficient handling of non-whitespace inputs in read_until_whitespace

Impact An attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires a call to readuntilwhitespace with an input which does not have whitespace for a long time. Patches This has been fixed in pypdf==6.15.0. Workarounds If you cannot upgrade yet, consider...

PYSEC-2026-3910 pypdf: Possible long runtimes/large memory usage when retrieving outlines

Impact An attacker who uses this vulnerability can craft a PDF which leads to long runtimes and large memory consumption. This requires accessing the outlines of a document with either lots of entries or nested outlines with long re-used nesting paths. Patches This has been fixed in pypdf==6.16.1...

PYSEC-2026-3913 pypdf: Possible infinite loop for TreeObject.insert_child

Impact An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires a usually writing code path where TreeObject.insertchild is involved. Patches This has been fixed in pypdf==6.16.0. Workarounds If you cannot upgrade yet, consider applying the changes fr...

PYSEC-2026-3872 Omnigent: Uploaded Agent Bundle Allows Authenticated Runner RCE via Python Callable Tools

Summary An authenticated user can upload a crafted agent bundle that defines a server-side Python callable tool. The server validates the uploaded bundle, but it does not block dangerous callable: paths in untrusted user-provided agent configs. When the tool is invoked, the runner imports and...

PYSEC-2026-3874 Omnigent: Shared Agent Bundle Overwrite Leads to Authenticated Runner RCE

Summary An authenticated user with edit access to their own session can overwrite a shared/template agent by uploading a full agent bundle through PUT /sessions/sessionid/agent. Shared/template agents are shown as not MCP-editable, but this upload path still accepts a replacement bundle. By addin...

PYSEC-2026-3918 Scrapy: S3DownloadHandler sends signed S3 requests over plaintext HTTP by default

Problem Scrapy’s S3DownloadHandler sends signed S3 requests over plaintext HTTP by default. A normal request like s3://bucket/key is converted into http://bucket.s3.amazonaws.com/key unless request.meta"issecure" is explicitly set. The generated request is then signed with configured AWS...

PYSEC-2026-3864 Material for MkDocs: DOM XSS in search suggestions via query parameter

Impact Material for MkDocs 7.2.0 through 9.7.6 contains a DOM-based cross-site scripting vulnerability in the optional search.suggest feature. A crafted q URL parameter could execute JavaScript in the documentation site's origin after user interaction. Patches The issue is fixed in Material for...

PYSEC-2026-3810 Banks: Path traversal in `DirectoryPromptRegistry.set()` allows arbitrary file write outside the registry root

Summary DirectoryPromptRegistry.set interpolates the attacker-controllable Prompt.name into a Path expression with no canonicalization. An application that derives the prompt name from request data lets a caller write attacker-controlled bytes outside the configured registry directory. Details...

PYSEC-2026-3863 Mistune: Denial of Service — RecursionError via Excessive Emphasis Markers in Markdown

Summary Mistune v3.3.2 is vulnerable to a Denial of Service DoS attack via uncontrolled recursion in the HTML rendering of deeply-nested emphasis tokens. By submitting Markdown containing approximately 1,000 consecutive asterisk characters, an attacker causes the Python process to crash with...

PYSEC-2026-3873 Omnigent Guardrail policy bypass: shell-command parser fails open in policies/builtins/_shell.py

Reporter: Aaron / Aeon — autonomous security agent https://github.com/aaronjmars/aeon Project: omnigent-ai/omnigent v0.1.0 Databricks — meta-harness running Claude Code / Codex / Pi "in check with policies and sandboxing" Component: omnigent/policies/builtins/shell.py shared parser → consumed by...

PYSEC-2026-3930 unstructured: Server-Side Request Forgery in the URL-based partitioning

Summary Server-Side Request Forgery in unstructured. The url= argument of partition, partitionhtml, and partitionmd is fetched via requests.get with no host validation. The response body is returned as Element text, so this is a full-read SSRF — attackers reach loopback admin APIs, internal HTTP...

PYSEC-2026-3911 pypdf: Possible long runtimes/large memory usage when extracting XForm objects

Impact An attacker who uses this vulnerability can craft a PDF which leads to long runtimes and large memory consumption. This requires extracting the text of a page with lots of XForm objects, where some of them might be re-used. Patches This has been fixed in pypdf==6.16.1. Workarounds If you...

PYSEC-2026-3923 sqlparse: Reindentation of tuple lists causes near-cap quadratic CPU consumption

Summary When SQL is formatted with reindentation enabled, ReindentFilter repeatedly rebuilds prefixes of the current statement to calculate token offsets. An attacker who controls SQL sent to this opt-in formatting path can supply a parenthesized tuple list that remains just below the...

PYSEC-2026-3875 Omnigent: Unvalidated os_env.cwd in agent bundle yields arbitrary host filesystem access on runners without OMNIGENT_RUNNER_WORKSPACE

Summary An authenticated, non-admin user can obtain arbitrary host-filesystem read/write and host environment-secret disclosure on an Omnigent runner by uploading an agent bundle whose osenv.cwd points outside any intended workspace e.g. / or /home/. The cwd field is taken verbatim from the bundl...

PYSEC-2026-3868 NLTK: Uncontrolled search path when invoking the Graphviz 'dot' binary

Two NLTK sites executed the Graphviz dot program by bare name, so process creation resolved it via the search path — and on Windows via the current working directory — rather than a validated absolute location. An attacker who can place a file named dot where resolution looks the CWD on Windows, ...

PYSEC-2026-3827 Django REST framework: Potential bypass of Django `DATA_UPLOAD_MAX_MEMORY_SIZE` when parsing oversized JSON and urlencoded request bodies via DRF `request.data`

Summary While investigating Django REST Framework's request parsing behavior, I identified that DRF's high-level request.data parsing appears to bypass Django's configured DATAUPLOADMAXMEMORYSIZE protection for application/json and application/x-www-form-urlencoded request bodies. In the tested...

PYSEC-2026-3928 Tornado: Urlencoded body parsing omits max_num_fields, so one request can stall the event loop

Summary Tornado parses application/x-www-form-urlencoded bodies with urllib.parse.parseqs and does not pass maxnumfields. A body made almost entirely of separators produces tens of millions of fields, and the parse happens on the event loop before the handler runs, so a single request stalls the...

PYSEC-2026-3942 Weblate has IDOR in GroupViewSet that allows authenticated project manager to gain unauthorized read access to any private project

Impact The API did not properly handle project- and workspace-scoped teams and allowed setting invalid configurations, including granting access to projects the user has no access to. Patches https://github.com/WeblateOrg/weblate/pull/19970 References Parts of this issue were independently report...

PYSEC-2026-3882 piccolo-admin has a privilege escalation issue - admin to superuser via session-token disclosure in GET /api/tables/sessions/.

Summary piccoloadmin uses a helper called superuservalidators to gate access to the user and session tables for non-superusers. The helper rejects PUT, PATCH, DELETE, and POST, but does not reject GET. The sessions table stores live session tokens in plaintext, and the token column is not marked...

PYSEC-2026-3906 Protego has exponential backtracking ReDoS in robots.txt URL wildcard matching

Problem description Protego constructs regular expressions to match URLs against robots.txt Allow: and Disallow: directives, see protego.urlpattern.URLPattern.preparepatternforregex. Every in the directive value is translated into a lazy .? regex piece, thus a specially crafted directive value wi...

PYSEC-2026-3941 Private Weblate projects vulnerable to observable object existence disclosure via globally scoped object lookups

Impact The several endpoints could leak object existence information to users who had no access to it by HTTP status code 403 instead of 404. Patches https://github.com/WeblateOrg/weblate/pull/19971 References Thanks to Yaohui Wang for reporting this via GitHub...

PYSEC-2026-3883 plone.app.event vulnerable to denial of service via iCalendar import

Impact By abusing the iCalendar import functionality, a logged-in editor could take the whole site offline, make the server reach into the internal network and read calendar files off disk SSRF, and store XSS. Patches The problem has been patched in plone.app.event. For Plone 6.2: upgrade to...

PYSEC-2026-3945 WsgiDAV MySQL provider has a blind SQL injection

Summary The sample MySQLBrowserProvider builds its SQL queries by concatenating strings, and the record key from the request URL goes straight into the WHERE clause with no escaping. Any user who can reach a share backed by this provider can inject SQL through the URL. Since these read shares are...

PYSEC-2026-3828 Django REST framework: AdminRenderer may disclose GET-protected data when rendering invalid write requests

Summary AdminRenderer may disclose data that would normally be protected by GET permissions when rendering a 400 Bad Request response for an invalid write request. If a view allows POST or another write method but denies GET, an invalid request rendered through AdminRenderer can invoke the view's...

PYSEC-2026-3884 plone.app.portlets vulnerable to denial of service via RSS feed portlet

Impact By adding an RSS portlet, and giving this a link to a very large file, a member can cause a denial of service attack, because Plone will use lots of memory. The member could also use different urls to try to get information about the internal network and open port numbers SSRF. A malicious...

PYSEC-2026-3917 RestrictedPython guard hooks can be shadowed via positional-only arguments

Impact RestrictedPython rewrites sensitive operations to go through guard hooks. Attribute access becomes getattrobj, name, item access becomes getitemobj, key, writes go through write, and print goes through print. The embedding application supplies these hooks to enforce its policy. Argument-na...

PYSEC-2026-3853 JupyterHub has Unauthenticated Denial of Service via Unbounded Username Logging on Failed Login

Impact Invalid input to login resulted in unbounded logging output. Only form-based Authenticators the default PAM Authenticator, but not the more widely used OAuthenticator are affected. Patches Upgrade to 5.5.0. Workarounds Use an Authenticator that doesn't use a login form, such as...

PYSEC-2026-3861 LiteLLM vulnerable to server-side template injection in the /prompts/test endpoint

BerriAI litellm =1.82.4 is vulnerable to Server-Side Template Injection SSTI, which allows unauthenticated remote attackers to execute arbitrary OS commands via a crafted dotpromptcontent parameter in the /prompts/test endpoint due to use of an unsandboxed jinja2.Environment...

PYSEC-2026-3809 asyncssh has an incomplete fix for CVE-2026-45309 — AuthorizedKeysFile %u still escapes the intended directory via a leading ~ (and weakly via ${ENV}) username substitution

Incomplete fix for CVE-2026-45309 GHSA-g794-3fmp-753h. The 2.23.0 guard that sanitises the SSH username before %u substitution in AuthorizedKeysFile blocks /, \ and .., but does not block a leading or $ENV, both of which are re-introduced by later expansion and reach the file open — defeating the...

PYSEC-2026-3943 WebOb: Open redirect in Location header normalization via leading C0 control / space characters

Summary This is a third follow-up to CVE-2024-42353 / GHSA-mg3v-6m49-jhp3 and CVE-2026-44889 / GHSA-fh3h-vg37-cc95. WebOb makes the Location header absolute when it serves a redirect. To stop a relative or protocol-relative target from redirecting users off-host, it checks the value for a URI...

PYSEC-2026-3919 senaite.core Vulnerable to Eval Injection and Missing Authorization

Summary An unauthenticated remote code execution vulnerability in the SENAITE JSON API allows any network-reachable attacker to execute arbitrary Python on the Zope worker process via a two-request anonymous chain. The /@@API/update route is reachable to anonymous callers and runs eval on...

PYSEC-2026-3855 kas Persistently Disables SSH Host Key Checking

Summary kas persistently disables SSH host key checking for the invoking user when internal SSH key setup is triggered via SSHPRIVATEKEY or SSHPRIVATEKEYFILE and no user-specific SSH configuration file exists so far. When this path is used, kas creates /.ssh/config with a global Host rule...

PYSEC-2026-3924 Starlette-Admin's unvalidated `order_by` parameter allows ordering by hidden columns (info-exposure oracle) and HTTP 500 DoS

Summary Affected versions of Starlette-Admin prior to 0.16.1 do not properly validate user-supplied sort and search parameters against the configured field allowlists. While the administrative UI restricts available fields based on field configuration, the backend accepts arbitrary field names...

PYSEC-2026-3851 icalendar has Algorithmic Complexity in Equality

Summary Component.eq compares subcomponents in O2^n time relative to nesting depth. Because the parser accepts arbitrarily nested components, a sub-kilobyte .ics file is enough to make a single equality check run for minutes or hang indefinitely. Any application that compares parsed components ==...

PYSEC-2026-3817 Trestle has Server-Side Template Injection (SSTI) via Recursive Template Re-evaluation of Untrusted Data

Impact A Server-Side Template Injection SSTI vulnerability exists in multiple locations of trestle's Jinja2 rendering pipeline due to a systemic pattern: untrusted data is re-parsed as Jinja2 template source code without sandboxing. This advisory tracks the root cause across all affected code...

PYSEC-2026-3808 asyncssh has SCP Path Traversal to Arbitrary File Write

| | | |---|---| | Product | asyncssh all versions through 2.23.0 | | Related | CVE-2019-6111 same class in OpenSSH | | Fix | AsyncSSH 2.23.1 | A malicious SSH server can write arbitrary files on the asyncssh SCP client's filesystem by sending filenames containing ../ traversal sequences. The SCP...

PYSEC-2026-3805 aiosmtplib: STARTTLS response injection

Impact When a connection is upgraded with STARTTLS, aiosmtplib reads the server's 220 go-ahead reply and immediately performs the TLS handshake without discarding any data still sitting in the receive buffer. Bytes the protocol read off the plaintext socket before the handshake survive across the...

PYSEC-2026-3829 djust authentication bypass: a login_required / on_mount LiveView mount redirect does not close the WebSocket, allowing an unauthenticated client to dispatch event-handler calls

Impact djust's LiveViewConsumer mounts a LiveView over a WebSocket. When a view is gated loginrequired / permissionrequired, or an onmount hook that returns a redirect and the connecting user is not authorized, the consumer sent the client a "type":"navigate","to":... redirect frame and then...

PYSEC-2026-3811 Chainlist has SSRF via MCP SSE and streamable-http transports that allows unauthenticated internal network access

Am I affected? Only if your deployment sets features.mcp.enabled = true in .chainlit/config.toml. MCP has been disabled by default since v2.7.0, so most Chainlit deployments are not affected. No authentication is required: /mcp is reachable by any client that can open a session. Summary When MCP ...

PYSEC-2026-3832 eml_parser vulnerable to DoS via deeply nested parens in Received headers

Summary emlparser strips parenthesised CFWS comments from Received: headers using a regex-based fix-point loop. The loop has quadratic time complexity in the number of nested parens. A single Received: header containing 5,000 nested parens causes 1.3 seconds of CPU saturation per parsed message;...

PYSEC-2026-3833 eml_parser has parser DoS via deeply nested parentheses in e-mail headers

Summary emlparser uses the email.utils.getaddresses function from the CPython standard library to parse e-mail headers that contain e-mail addresses such as To, Cc, Bcc, From, Reply-To, Sender, .... When the input header contains a deeply nested CFWS comment / folding white space construct, the...

PYSEC-2026-3914 qwed Vulnerable to Authenticated Remote Code Execution via Unsafe SymPy `parse_expr()`

Summary The qwed package version 5.1.1 passes attacker-controlled input directly to SymPy's parseexpr function without a restricted namespace. Because parseexpr internally calls Python's eval, any authenticated tenant can execute arbitrary Python code inside the API server process. The attack...

PYSEC-2026-3916 reachy_mini Allows Unrestricted Upload of File with Dangerous Type

Summary The Reachy Mini daemon exposes the “/api/media/sounds/upload” endpoint without authentication and file validation mechanisms. An attacker can use this endpoint to upload malicious files into the file system that will propagate in future attacks. Compromise Chain: Unauthenticated to Full...

PYSEC-2026-3866 nextcloud-mcp-server: Unauthenticated `POST /webhooks/nextcloud` allows arbitrary vector data deletion when `WEBHOOK_SECRET` is unset ( default )

Summary The POST /webhooks/nextcloud endpoint has no authentication by default: WEBHOOKSECRET defaults to None and is never required by startup validation. When unset, the receiver accepts any unauthenticated POST. The userid is taken directly from the attacker-supplied payload and passed to...