PSF-2025-5

Allows modifying some file metadata e.g. last modified with filter="data" or file permissions chmod with filter="tar" of files outside the extraction directory. You are affected by this vulnerability if using the tarfile module to extract untrusted tar archives using TarFile.extractall or...

PSF-2025-8

When using a TarFile.errorlevel = 0 and extracting with a filter the documented behavior is that any filtered members would be skipped and not extracted. However the actual behavior of TarFile.errorlevel = 0 in affected versions is that the member would still be extracted and not skipped...

PSF-2025-6

Allows the extraction filter to be ignored, allowing symlink targets to point outside the destination directory, and the modification of some file metadata. You are affected by this vulnerability if using the tarfile module to extract untrusted tar archives using TarFile.extractall or...

PSF-2025-7

Allows the extraction filter to be ignored, allowing symlink targets to point outside the destination directory, and the modification of some file metadata. You are affected by this vulnerability if using the tarfile module to extract untrusted tar archives using TarFile.extractall or...

PSF-2025-3

During an address list folding when a separating comma ends up on a folded line and that line is to be unicode-encoded then the separator itself is also unicode-encoded. Expected behavior is that the separating comma remains a plan comma. This can result in the address header being misinterpreted...

PSF-2025-2

There is a defect in the CPython standard library module “mimetypes” where on Windows the default list of known file locations are writable meaning other users can create invalid files to cause MemoryError to be raised on Python runtime startup or have file extensions be interpreted as the...

PSF-2025-1

The Python standard library functions urllib.parse.urlsplit and urlparse accepted domain names that included square brackets which isn't valid according to RFC 3986. Square brackets are only meant to be used as delimiters for specifying IPv6 and IPvFuture hosts in URLs. This could result in...

PSF-2024-13

The urllib.parse.urlsplit and urlparse functions improperly validated bracketed hosts , allowing hosts that weren't IPv6 or IPvFuture. This behavior was not conformant to RFC 3986 and potentially enabled SSRF if a URL is processed by more than one URL parser...

PSF-2024-12

A vulnerability has been found in the CPython venv module and CLI where path names provided when creating a virtual environment were not quoted properly, allowing the creator to inject commands into virtual environment "activation" scripts ie "source venv/bin/activate". This means that...

PSF-2024-11

There is a MEDIUM severity vulnerability affecting CPython. Regular expressions that allowed excessive backtracking during tarfile.TarFile header parsing are vulnerable to ReDoS via specifically-crafted tar archives...

PSF-2024-10

There is a HIGH severity vulnerability affecting the CPython "zipfile" module affecting "zipfile.Path". Note that the more common API "zipfile.ZipFile" class is unaffected. When iterating over names of entries in a zip archive for example, methods of "zipfile.Path" like "namelist", "iterdir", etc...

PSF-2024-9

There is a LOW severity vulnerability affecting CPython, specifically the 'http.cookies' standard library module. When parsing cookies that contained backslashes for quoted characters in the cookie value, the parser would use an algorithm with quadratic complexity, resulting in excess CPU resourc...

PSF-2024-7

The “socket” module provides a pure-Python fallback to the socket.socketpair function for platforms that don’t support AFUNIX, such as Windows. This pure-Python implementation uses AFINET or AFINET6 to create a local connected pair of sockets. The connection between the two sockets was not verifi...

PSF-2024-6

CPython 3.9 and earlier doesn't disallow configuring an empty list "" for SSLContext.setnpnprotocols which is an invalid value for the underlying OpenSSL API. This results in a buffer over-read when NPN is used see CVE-2024-5535 for OpenSSL. This vulnerability is of low severity due to NPN being...

PSF-2024-4

A defect was discovered in the Python “ssl” module where there is a memory race condition with the ssl.SSLContext methods “certstorestats” and “getcacerts”. The race condition can be triggered if the methods are called at the same time as certificates are loaded into the SSLContext, such as durin...

PSF-2024-3

On Windows a directory returned by tempfile.mkdtemp would not always have permissions set to restrict reading and writing to the temporary directory by other users, instead usually inheriting the correct permissions from the default location. Alternate configurations or users without a profile...

PSF-2024-1

An issue was found in the CPython tempfile.TemporaryDirectory class affecting versions 3.12.1, 3.11.7, 3.10.13, 3.9.18, and 3.8.18 and prior. The tempfile.TemporaryDirectory class would dereference symlinks during cleanup of permissions-related errors. This means users which can run privileged...

PSF-2024-2

An issue was found in the CPython zipfile module affecting versions 3.12.1, 3.11.7, 3.10.13, 3.9.18, and 3.8.18 and prior. The zipfile module is vulnerable to “quoted-overlap” zip-bombs which exploit the zip format to create a zip-bomb with a high compression ratio. The fixed versions of CPython...

PSF-2023-12 Groups not dropped before running subprocess when using empty 'extra_groups' parameter

An issue was found in CPython 3.12.0 subprocess module on POSIX platforms. The issue was fixed in CPython 3.12.1 and does not affect other stable releases. When using the extragroups= parameter with an empty list as a value ie extragroups= the logic regressed to not call setgroups0, NULL before...

PSF-CVE-2023-6507 Groups not dropped before running subprocess when using empty 'extra_groups' parameter

An issue was found in CPython 3.12.0 subprocess module on POSIX platforms. The issue was fixed in CPython 3.12.1 and does not affect other stable releases. When using the extragroups= parameter with an empty list as a value ie extragroups= the logic regressed to not call setgroups0, NULL before...

PSF-2023-5 XML External Entity issue in plistlib module

An XML External Entity XXE issue was discovered in Python through 3.9.1. The plistlib module no longer accepts entity declarations in XML plist files to avoid XML vulnerabilities...

PSF-2023-8 Bypass TLS handshake on closed sockets

Instances of ssl.SSLSocket are vulnerable to a bypass of the TLS handshake and included protections like certificate verification and treating sent unencrypted data as if it were post-handshake TLS encrypted data. The vulnerability is caused when a socket is connected, data is sent by the malicio...

PSF-2023-9 os.path.normpath() truncates on null bytes

Passing a path with null bytes to the os.path.normpath function causes the returned path to be unexpectedly truncated at the first occurrence of null bytes within the path. Python versions before 3.11.0 didn’t truncate the path on null bytes. If allowlisting is applied before a call to...

PSF-2023-6 hmac.compare_digest() accumulator not constant-time

An issue was discovered in comparedigest in Lib/hmac.py in Python through 3.9.1. Constant-time-defeating optimisations were possible in the accumulator variable in hmac.comparedigest...

PSF-2023-10 DoS when reading malformed Apple Property List files in binary format

readints in plistlib.py in Python through 3.9.1 is vulnerable to a potential DoS attack via CPU and RAM exhaustion when processing malformed Apple Property List files in binary format...

PSF-2023-11 Use-after-free in heappushpop() of heapq module

A use-after-free exists in Python through 3.9 via heappushpop in heapq...

PSF-2023-7 Reference count issue in _asyncio._swap_current_task()

An issue in Python CPython 3.12.0b1 allows an attacker to obtain sensitive information via the asyncio.swapcurrenttask component...

PSF-2023-4

The legacy email.utils.parseaddr function in Python through 3.11.4 allows attackers to trigger "RecursionError: maximum recursion depth exceeded while calling a Python object" via a crafted argument. This argument is plausibly an untrusted value from an application's input data that was supposed ...

PSF-2023-3

CPython v3.12.0 alpha 7 was discovered to contain a heap use-after-free via the function asciidecode at /Objects/unicodeobject.c...

PSF-2023-2 Parsing errors in email/_parseaddr.py lead to incorrect value in email address part of tuple

The email module of Python through 3.11.3 incorrectly parses e-mail addresses that contain a special character. The wrong portion of an RFC2822 header is identified as the value of the addr-spec. In some applications, an attacker can bypass a protection mechanism in which application access is...

PSF-2023-1 urlparse does not correctly handle schemes

An issue in the urllib.parse component of Python before 3.11.4 allows attackers to bypass blocklisting methods by supplying a URL that starts with blank characters...

PSF-2022-10 Slow IDNA decoding with large strings

An issue was discovered in Python before 3.11.1. An unnecessary quadratic algorithm exists in one path when processing some inputs to the IDNA RFC 3490 decoder, such that a crafted, unreasonably long name being presented to the decoder could lead to a CPU denial of service. Hostnames are often...

PSF-2022-9 Linux specific local privilege escalation via the multiprocessing forkserver start method

Python 3.9.x before 3.9.16 and 3.10.x before 3.10.9 on Linux allows local privilege escalation in a non-default configuration. The Python multiprocessing library, when used with the forkserver start method on Linux, allows pickles to be deserialized from any user in the same machine local network...

PSF-2022-11 Buffer overflow in the _sha3 module in Python 3.10 and older

The Keccak XKCP SHA-3 reference implementation before fdc6fef has an integer overflow and resultant buffer overflow that allows attackers to execute arbitrary code or eliminate expected cryptographic properties. This occurs in the sponge function interface...

PSF-2022-2 Buffer overflow vulnerability in os.symlink on Windows

Python Software Foundation CPython version From 3.2 until 3.6.4 on Windows contains a Buffer Overflow vulnerability in os.symlink function on Windows that can result in Arbitrary code execution, likely escalation of privilege. This attack appears to be exploitable via a python script that creates...

PSF-2022-4 Prevent DoS by large str-int conversions

A flaw was found in python. In algorithms with quadratic time complexity using non-binary bases, when using int"text", a system could take 50ms to parse an int string with 100,000 digits and 5s for 1,000,000 digits float, decimal, int.frombytes, and int for binary bases 2, 4, 8, 16, and 32 are no...

PSF-2022-5 http.server: Open Redirection if the URL path starts with //

Python 3.x through 3.10 has an open redirection vulnerability in lib/http/server.py due to no protection against multiple / at the beginning of URI path which may leads to information disclosure. NOTE: this is disputed by a third party because the http.server.html documentation page states...

PSF-2022-1 mailcap shell command injection

In Python aka CPython up to 3.10.8, the mailcap module does not add escape characters into commands discovered in the system mailcap file. This may allow attackers to inject shell commands into applications that call mailcap.findmatch with untrusted input if they lack validation of user-provided...

PSF-2022-3 Windows: vulnerable zlib 1.2.11

zlib before 1.2.12 allows memory corruption when deflating i.e., when compressing if the input has many distant matches...

PSF-2022-6 CVE-2021-3733: ReDoS in urllib.request

There's a flaw in urllib's AbstractBasicAuthHandler class. An attacker who controls a malicious HTTP server that an HTTP client such as web browser connects to, could trigger a Regular Expression Denial of Service ReDOS during an authentication request with a specially crafted payload that is sen...

PSF-2022-7 CVE-2021-3737: urllib HTTP client possible infinite loop on a 100 Continue response

A flaw was found in python. An improperly handled HTTP response in the HTTP client code of python may allow a remote attacker, who controls the HTTP server, to make the client script enter an infinite loop, consuming CPU time. The highest threat from this vulnerability is to system availability...

PSF-2022-8 urllib.parse should sanitize urls containing ASCII newline and tabs.

A flaw was found in Python, specifically within the urllib.parse module. This module helps break Uniform Resource Locator URL strings into components. The issue involves how the urlparse method does not sanitize input and allows characters like '\r' and '\n' in the URL path. This flaw allows an...

PSF-2021-4 Information disclosure via pydoc getfile

There's a flaw in Python 3's pydoc. A local or adjacent attacker who discovers or is able to convince another local or adjacent user to start a pydoc server could access the server and use it to disclose sensitive information belonging to the other user that they would not normally be able to...

PSF-2021-2 ipaddress leading zeros in IPv4 address

In Python before 3,9,5, the ipaddress library mishandles leading zero characters in the octets of an IP address string. This in some situations allows attackers to bypass access control that is based on IP addresses...

PSF-2021-5 ftplib should not use the host from the PASV response

The IPv4 address value returned from the server in response to the PASV command should not be trusted. This prevents a malicious FTP server from using the response to probe IPv4 address and port combinations on the client network. Instead of using the returned address, we use the IP address we're...

PSF-2021-1 urllib parse_qsl(): Web cache poisoning - semicolon as a query args separator

The package python/cpython from 0 and before 3.6.13, from 3.7.0 and before 3.7.10, from 3.8.0 and before 3.8.8, from 3.9.0 and before 3.9.2 are vulnerable to Web Cache Poisoning via urllib.parse.parseqsl and urllib.parse.parseqs by using a vector called parameter cloaking. When the attacker can...

PSF-2021-3 ctypes: Buffer overflow in PyCArg_repr

Python 3.x through 3.9.1 has a buffer overflow in PyCArgrepr in ctypes/callproc.c, which may lead to remote code execution in certain Python applications that accept floating-point numbers as untrusted input, as demonstrated by a 1e300 argument to cdouble.fromparam. This occurs because sprintf is...

PSF-2020-5 http.client: HTTP Header Injection in the HTTP method

http.client in Python 3.x before 3.5.10, 3.6.x before 3.6.12, 3.7.x before 3.7.9, and 3.8.x before 3.8.5 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by inserting CR and LF control characters in the first argument of HTTPConnection.request...

PSF-2020-2 Infinite loop in tarfile module while opening a crafted file

In Lib/tarfile.py in Python through 3.8.3, an attacker is able to craft a TAR archive leading to an infinite loop when opened by tarfile.open, because procpax lacks header validation...

PSF-2020-4 Py_SetPath(): _Py_CheckPython3 uses uninitialized DLL path

In Python 3.6 through 3.6.10, 3.7 through 3.7.8, 3.8 through 3.8.4rc1, and 3.9 through 3.9.0b4 on Windows, a Trojan horse python3.dll might be used in cases where CPython is embedded in a native application. This occurs because python3X.dll may use an invalid search path for python3.dll loading...