CVE-2020-11945

Squid vulnerability CVE-2020-11945 is confirmed in various advisories for Squid prior to 5.0.2, where a remote attacker can replay a sniffed Digest Authentication nonce due to overflow of the nonce reference counter, potentially enabling remote code execution if pooled token credentials are freed...

CVE-2019-12525

CVE-2019-12525 affects Squid (3.3.9–3.5.28 and 4.x–4.7). When Digest authentication is used, Proxy-Authorization parsing may treat a single quote as valid and memcpy with length−1, causing memory corruption. Connected advisories confirm the issue and reference updates to Squid versions; however e...

CVE-2019-12522

CVE-2019-12522 (Squid) affects Squid up to version 4.7. When Squid runs as root, its child processes are spawned as a lesser user (default: nobody). The code path uses leave_suid, which leaves the Saved UID as 0, enabling an attacker who compromises a child process to escalate privileges back to ...

CVE-2020-8450

CVE-2020-8450 affects Squid prior to 4.10, caused by incorrect buffer management in reverse-proxy mode, allowing a remote client to trigger a buffer overflow. Connected advisories confirm a fix was released (e.g., updates to Squid 4.11+/4.10-era patches) across multiple distributions (CloudLinux,...

CVE-2019-12526

CVE-2019-12526 affects Squid prior to 4.9, where URN response handling can overflow the heap with attacker-controlled data when processing URN responses from a remote server. The connected advisories confirm that a fix is available in newer upstream versions (e.g., 4.10+ as reflected in ALT Linux...

CVE-2019-12519

CVE-2019-12519 in Squid (up to 4.7) originates from ESI handling: ESIExpression::Evaluate uses a fixed stack buffer and does not check for overflow when adding a new member, causing a stack/heap overflow under certain expressions and potentially impacting confidentiality, integrity, and availabil...

CVE-2020-15049

CVE-2020-15049 affects Squid up to 4.12 and 5.x up to 5.0.3. It enables a Request Smuggling and Poisoning attack against the HTTP cache by sending Content-Length values with a prefix like +, - or uncommon whitespace. Affected component: http/ContentLengthInterpreter.cc. Impact: potential cache po...

CVE-2025-62168

Squid (proxy/cache) prior to version 7.2 is affected by information disclosure due to failure to redact HTTP authentication credentials in error handling. The vulnerability can allow a remote, unauthenticated attacker to learn credentials or tokens used by a trusted client or internal web applica...

CVE-2020-25097

CVE-2020-25097 affects Squid proxy (versions 4.13 and 5.x up to 5.0.4) due to improper input validation while parsing request URIs, enabling HTTP request smuggling by a trusted client and access to services otherwise restricted. The issue is activated for certain uri_whitespace configurations. Pu...

CVE-2019-13345

CVE-2019-13345 : XSS in the cachemgr.cgi web module of Squid through 4.7, exploitable via the user_name or auth parameter. Connected advisories confirm multiple distributions issue fixes and recommended upgrades (e.g., Debian DSA-4507, CentOS/RHEL advisories, ALAS-2 entries). The exposure is limi...

CVE-2021-28651

Concrete details found for CVE-2021-28651 in multiple advisories. Affected software: Squid proxy (versions before 4.15 and 5.x before 5.0.6). Root cause: a buffer-management/memory handling issue in the urn: scheme parsing leading to a memory leak; an attack path exists that can trigger large mem...

CVE-2020-24606

Squid vulnerability CVE-2020-24606 affects Squid 4.13 and 5.x prior to 5.0.4, where a trusted peer can cause a Denial of Service by exhausting CPU cycles while handling a crafted Cache Digest response. Root cause: peerDigestHandleReply() livelock due to EOF mishandling in peer_digest.cc. Impact i...

CVE-2019-12523

CVE-2019-12523 affects Squid prior to 4.9, where handling a URN request transforms it into an HTTP request that bypasses the standard incoming HTTP access checks. This allows an attacker to access restricted HTTP servers (e.g., localhost) by bypassing ACLs via the URN path, with potential exposur...

CVE-2023-46846

Squid (proxy server) is affected by CVE-2023-46846 due to chunked decoder lenience, enabling potential HTTP request smuggling past controls. Public docs in the connected sources confirm the vulnerability in Squid, noting that parsing HTTP/1.1 and ICAP messages can lead to bypassing security contr...

CVE-2019-12529

CVE-2019-12529 affects Squid 2.x–4.x (up to 4.7) where Basic Authentication parsing decodes Proxy-Authorization using uudecode. The decoder does not validate that the calculated decode length fits the input buffer, causing adjacent memory to be decoded and enabling a potential DoS via out-of-boun...

CVE-2021-46784

The CVE-2021-46784 issue affects Squid 3.x–3.5.28, 4.x–4.17, and 5.x prior to 5.6, caused by improper buffer management that can lead to a Denial of Service when processing long Gopher server responses. Affected releases are vulnerable to DoS; remediation is to update to a fixed version (5.6 or l...

CVE-2019-18679

The CVE-2019-18679 issue affects Squid 2.x–4.x (through 4.8) and arises from incorrect data management during HTTP Digest Authentication, where nonce tokens contain the raw pointer byte value from heap memory. This information disclosure reduces ASLR effectiveness and could assist attackers targe...

CVE-2019-12528

Squid is affected by CVE-2019-12528 (pre-4.10). A crafted FTP server can trigger disclosure of sensitive data from heap memory, including data from other sessions or non-Squid processes. Remediation in affected advisories involves upgrading Squid to a later version (at least 4.10+; many advisorie...

CVE-2023-46847

CVE-2023-46847 affects the Squid proxy: a DoS possibility via a Denial of Service caused by a heap buffer overflow when parsing HTTP Digest Authentication, by writing up to 2 MB of arbitrary data. Affected component is the Digest Authentication parsing in Squid; impact is primarily availability (...

CVE-2019-18677

CVE-2019-18677 affects Squid 3.x and 4.x up to 4.8 where the append_domain setting can cause improper message processing, leading to traffic being redirected to origins that should not be delivered to. This is confirmed in multiple advisories (e.g., ALAS2-2023-2318) listing CVE-2019-18677 as a se...

CVE-2020-8449

CVE-2020-8449 affects Squid prior to 4.10. The issue arises from improper input validation in HTTP request processing , allowing crafted requests to access resources that should be blocked by security filters. The connected advisories confirm a fix was released across multiple distributions (e.g....

CVE-2019-18676

CVE-2019-18676 affects Squid 3.x and 4.x up to 4.8, where incorrect input validation enables a heap-based buffer overflow that can cause a Denial of Service to all clients using the proxy. The connected advisories describe the issue scope and related CVEs in the same Squid codebase (URn/URI proce...

CVE-2019-12521

CVE-2019-12521 is a Squid vulnerability where, while parsing ESI, the ESIContext buffer used to hold ESIElements is overflowed due to an off-by-one bug in addStackElement. The overflow is within the same structure and causes a crash during processing (not adjacent memory corruption). Affected: Sq...

CVE-2019-18678

CVE-2019-18678 affects Squid 3.x and 4.x up to 4.8. It arises from a request header with whitespace between a header name and a colon, enabling an attacker to smuggle HTTP requests through frontend software to a Squid instance. The resulting Response messages corrupt caches between the client and...

CVE-2021-28652

CVE-2021-28652 concerns Squid before 4.15 and 5.x before 5.0.6. The issue stems from incorrect parser validation, allowing a Denial of Service attack against the Cache Manager API. A trusted client with Cache Manager API access can trigger memory leaks that, over time, lead to a DoS via an unspec...

CVE-2021-31807

CVE-2021-31807: Squid before 4.15 and 5.x before 5.0.6 suffers an integer overflow in handling HTTP Range responses, enabling a remote attacker to cause a Denial of Service. The trigger is a header that can appear in normal traffic. Affected products/versions: Squid 4.x before 4.15 and 5.x before...

CVE-2018-1000027

Summary (CVE-2018-1000027) The Squid HTTP Caching Proxy (Squid Software Foundation) versions prior to 4.0.23 contain a NULL Pointer Dereference vulnerability in HTTP Response X-Forwarded-For header processing that can cause a Denial of Service for all clients of the proxy. Exploitation appears po...

CVE-2019-18860

CVE-2019-18860 affects Squid before 4.9; it mishandles HTML in the host (hostname) parameter to cachemgr.cgi when certain browsers are used. Root cause is improper parsing of that parameter, leading to insecure behavior. The vulnerability is addressed in Squid 4.9+ (upgrade suggested). Exploitati...

CVE-2021-31806

CVE-2021-31806 is a memory-management bug in Squid’s HTTP Range request processing that enables a Denial of Service against all clients using the proxy. Affected are Squid releases before 4.15 and 5.x before 5.0.6. Public advisories and vendor/procurer notes corroborate impact as DoS (not informa...

CVE-2020-15810

CVE-2020-15810 affects Squid before 4.13 and 5.x before 5.0.4. Due to incorrect data validation, HTTP Request Smuggling may succeed against HTTP/HTTPS traffic, leading to cache poisoning and the ability for arbitrary content to be served from upstream caches. When relaxed header parsing is enable...

CVE-2018-1000024

The CVE-2018-1000024 vulnerability affects Squid HTTP Caching Proxy (versions 3.0–3.5.27 and 4.0–4.0.22). It is caused by Incorrect Pointer Handling in ESI Response Processing, enabling a Denial of Service when a remote server delivers an HTTP response payload with valid but unusual ESI syntax. I...

CVE-2021-28116

Squid 4.14 and 5.x up to 5.0.5 are affected by an information-disclosure issue due to an out-of-bounds read in WCCP protocol data, which can be chained to remote code execution as nobody. The connected advisories/entries indicate fixes in newer Squid releases (e.g., subsequent 4.15/5.0.6+ variant...

CVE-2019-12527

CVE-2019-12527 affects Squid 4.0.23–4.7. The issue arises in Basic Authentication handling: HttpHeader::getAuth decodes the Base64 blob into a fixed-size buffer without confirming decoded length, causing a heap-based buffer overflow with user-controlled data. Some sources note this can lead to re...

CVE-2021-28662

CVE-2021-28662 affects Squid 4.x before 4.15 and 5.x before 5.0.6. A remote server sending a certain HTTP/HTTPS response header can trigger a denial-of-service in the proxy via input/response handling. This is the same class of DoS as described in multiple advisories (e.g., Arch Linux, Debian, Al...

CVE-2019-12524

CVE-2019-12524 concerns Squid up to version 4.7 where the Cache Manager block relies on a url_regex rule that decodes incoming requests. An attacker can craft an encoded URL to bypass the url_regex check and access the blocked Cache Manager resource. Affects Squid’s request handling path and deco...

CVE-2020-15811

CVE-2020-15811 affects Squid before 4.13 and 5.x before 5.0.4, allowing HTTP Request Splitting that can poison caches by mishandling Transfer-Encoding. The issue is confirmed in vendor advisories (ALAS2SQUID4-2023-006; ALAS-2020-1453; ALAS2-2020-1548) which recommend updating Squid to fixed build...

CVE-2020-8517

CVE-2020-8517 affects Squid prior to 4.10. The issue is an out-of-bounds write in the NTLM credentials parser within ext_lm_group_acl caused by incorrect input validation. This can terminate the helper process, which in turn terminates the Squid process and leads to a denial of service for all cl...

CVE-2021-33620

Summary: CVE-2021-33620 affects Squid before 4.15 and 5.x before 5.0.6. It can cause a denial of service across all clients via an HTTP response, triggered by a header that can appear in legitimate traffic. What’s affected: Squid proxy/cache (core components handling HTTP traffic). Root cause (pe...

CVE-2020-14058

CVE-2020-14058 affects Squid before 4.12 and 5.x before 5.0.3. The DoS condition occurs when opening a TLS connection to an attacker-controlled HTTPS server due to using a potentially dangerous function and mapping unrecognized error values to NULL, with later code expecting valid error strings. ...

CVE-2022-41318

CVE-2022-41318 is a vulnerability in Squid’s libntlmauth where a buffer over-read, caused by insufficient integer-overflow protection in the SSPI/SMB authentication helpers, can lead to reading unintended memory and potentially exposing cleartext credentials to a client. Public sources consistent...

CVE-2021-31808

CVE-2021-31808 affects Squid before 4.15 and 5.x before 5.0.6. It stems from an input-validation bug in HTTP Range handling that can be exploited to cause a Denial of Service against all clients using the proxy. Affected component: Squid’s HTTP Range request processing. Impact: availability degra...

CVE-2024-25111

Squid (web proxy cache) is affected by CVE-2024-25111. Affected versions are 3.5.27 up to, but not including, 6.8; the issue is an uncontrolled recursion in the HTTP Chunked decoder that can cause a remote DoS when processing crafted chunked HTTP messages. The vulnerability is fixed in Squid vers...

CVE-2022-41317

Squid CVE-2022-41317 affects versions 4.9–4.17 and 5.0.6–5.6; due to inconsistent handling of internal URIs, there is Exposure of Sensitive Information about clients via an HTTPS request to an internal cache manager URL. The issue is fixed in version 5.7. Remediation: update Squid to 5.7 or apply...

CVE-2023-5824

Summary: CVE-2023-5824 affects Squid. A flaw in how HTTP response headers are validated before caching allows a header to exceed the configured maximum size, causing a stall or crash of a worker process and resulting in a denial of service. What’s affected: Squid proxy caching server; multiple ad...

CVE-2016-10002

CVE-2016-10002 impacts Squid HTTP Proxy. The issue arises from incorrect handling of If-None-Modified responses, where connection-specific cookie data could be leaked across clients due to not removing headers when serving cached responses. Affected Squid lines include 3.1.10–3.1.23, 3.2.0.3–3.5....

CVE-2019-12854

CVE-2019-12854 affects Squid up to 4.7, where incorrect string termination in cachemgr.cgi can cause access to unallocated memory and DoS for clients. Public advisories document this as a Denial of Service vector and list Squid 4.0–4.7 as affected; remediation seen in later vendor advisories/upda...

CVE-2018-19132

CVE-2018-19132 : In Squid, a memory leak occurs when SNMP is enabled, exploitable via SNMP packets to cause denial of service by resource exhaustion. Public advisories confirm a fix in newer Squid releases across multiple distros (e.g., Debian squid3 updates, Mageia 2018-0458, Amazon ALAS/SR pack...

CVE-2025-54574

Summary: CVE-2025-54574 affects Squid proxy. In versions 6.3 and older, URN processing causes a heap buffer overflow that can enable remote code execution. Fix released in 6.4; workaround: disable URN access permissions. Multiple advisories (Debian, CloudLinux, Astra Linux, Fedora, etc.) corrobor...

CVE-2018-19131

CVE-2018-19131 affects Squid prior to 4.4, enabling cross-site scripting via a crafted X.509 certificate during HTTP(S) error page generation for certificate errors. Connected advisories confirm the issue and provide fixes: Amazon Linux 2 ALAS2-2023-2310 lists updated squid packages (e.g., squid-...

CVE-2019-12520

CVE-2019-12520 affects Squid (versions up to 4.7 and 5.x per the sources). The vulnerability arises when Squid handles a request by computing an MD5 hash of the absolute URL to check the cache; if the URL includes a decoded UserInfo (username:password), that info is prepended to the domain. An at...