CVE-2021-23336

NameCVE-2021-23336
DescriptionThe 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.parse_qsl and urllib.parse.parse_qs by using a vector called parameter cloaking. When the attacker can separate query parameters using a semicolon (;), they can cause a difference in the interpretation of the request between the proxy (running with default configuration) and the server. This can result in malicious requests being cached as completely safe ones, as the proxy would usually not see the semicolon as a separator, and therefore would not include it in a cache key of an unkeyed parameter.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub advisories/code/issues, web search, more)
ReferencesDLA-2569-1, DLA-2619-1, DLA-2628-1
Debian Bugs983090

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
pypy3 (PTS)buster7.0.0+dfsg-3vulnerable
bullseye7.3.5+dfsg-2+deb11u1fixed
bookworm, sid7.3.9+dfsg-4fixed
python-django (PTS)buster, buster (security)1:1.11.29-1~deb10u1vulnerable
bullseye2:2.2.26-1~deb11u1fixed
bookworm, sid3:3.2.15-1fixed
python2.7 (PTS)buster2.7.16-2+deb10u1vulnerable
bullseye2.7.18-8vulnerable
bookworm, sid2.7.18-13.2fixed
python3.7 (PTS)buster3.7.3-2+deb10u3vulnerable
python3.9 (PTS)bullseye3.9.2-1fixed
sid3.9.13-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
pypy3source(unstable)7.3.3+dfsg-3
python-djangosourcestretch1:1.10.7-2+deb9u11DLA-2569-1
python-djangosource(unstable)2:2.2.19-1983090
python2.7sourceexperimental2.7.18-13.1~exp1
python2.7sourcestretch2.7.13-2+deb9u5DLA-2628-1
python2.7source(unstable)2.7.18-13.1
python3.5sourcestretch3.5.3-1+deb9u4DLA-2619-1
python3.5source(unstable)(unfixed)
python3.7source(unstable)(unfixed)
python3.8source(unstable)(unfixed)
python3.9source(unstable)3.9.2-1

Notes

[buster] - python-django <no-dsa> (Minor issue; can be fixed via point release)
[buster] - python3.9 <ignored> (Will break existing applications, don't backport to released suites)
[buster] - python3.7 <ignored> (Will break existing applications, don't backport to released suites)
[bullseye] - python2.7 <ignored> (Python 2.7 in Bullseye not covered by security support)
[buster] - python2.7 <ignored> (Will break existing applications, don't backport to released suites)
[buster] - pypy3 <no-dsa> (Minor issue)
https://github.com/python/cpython/pull/24297
https://github.com/python/cpython/commit/fcbe0cb04d35189401c0c880ebfb4311e952d776 (master)
https://github.com/python/cpython/commit/c9f07813ab8e664d8c34413c4fc2d4f86c061a92 (3.9)
https://github.com/python/cpython/commit/d0d4d30882fe3ab9b1badbecf5d15d94326fd13e (3.7)
https://snyk.io/blog/cache-poisoning-in-popular-open-source-packages/

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