CVE-2021-3426

NameCVE-2021-3426
DescriptionThere'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 access. The highest risk of this flaw is to data confidentiality. This flaw affects Python versions before 3.8.9, Python versions before 3.9.3 and Python versions before 3.10.0a7.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)
ReferencesDLA-2619-1
NVD severitylow

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
pypy3 (PTS)buster7.0.0+dfsg-3vulnerable
bullseye, sid7.3.5+dfsg-2fixed
python2.7 (PTS)stretch2.7.13-2+deb9u3fixed
stretch (security)2.7.13-2+deb9u5fixed
buster2.7.16-2+deb10u1fixed
bullseye, sid2.7.18-8fixed
python3.5 (PTS)stretch3.5.3-1+deb9u1vulnerable
stretch (security)3.5.3-1+deb9u4fixed
python3.7 (PTS)buster3.7.3-2+deb10u3vulnerable
python3.9 (PTS)bullseye, sid3.9.2-1vulnerable

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
pypy3source(unstable)7.3.3+dfsg-4
python2.7source(unstable)(not affected)
python3.5sourcestretch3.5.3-1+deb9u4DLA-2619-1
python3.5source(unstable)(unfixed)
python3.7source(unstable)(unfixed)
python3.9sourceexperimental3.9.3-1
python3.9source(unstable)(unfixed)

Notes

[bullseye] - python3.9 <no-dsa> (Minor issue)
[buster] - python3.7 <no-dsa> (Minor issue)
- python2.7 <not-affected> (Vulnerable code not present)
[buster] - pypy3 <no-dsa> (Minor issue)
https://bugs.python.org/issue42988
https://github.com/python/cpython/commit/9b999479c0022edfc9835a8a1f06e046f3881048
https://python-security.readthedocs.io/vuln/pydoc-getfile.html
https://github.com/python/cpython/pull/24337
https://github.com/python/cpython/pull/24285

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