CVE-2021-3737

NameCVE-2021-3737
DescriptionA 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.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDLA-2808-1, DLA-3432-1, DLA-3477-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
python2.7 (PTS)buster2.7.16-2+deb10u1vulnerable
buster (security)2.7.16-2+deb10u4fixed
bullseye2.7.18-8+deb11u1vulnerable
python3.7 (PTS)buster3.7.3-2+deb10u3vulnerable
buster (security)3.7.3-2+deb10u7fixed
python3.9 (PTS)bullseye3.9.2-1vulnerable

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
python2.7sourcebuster2.7.16-2+deb10u2DLA-3432-1
python2.7source(unstable)(unfixed)
python3.4source(unstable)(unfixed)
python3.5sourcestretch3.5.3-1+deb9u5DLA-2808-1
python3.5source(unstable)(unfixed)
python3.7sourcebuster3.7.3-2+deb10u5DLA-3477-1
python3.7source(unstable)(unfixed)
python3.9sourceexperimental3.9.6-1
python3.9source(unstable)3.9.7-1

Notes

[bullseye] - python3.9 <no-dsa> (Minor issue)
[bullseye] - python2.7 <ignored> (Unsupported in Bullseye, only included to build a few applications)
https://bugs.python.org/issue44022
https://github.com/python/cpython/pull/25916
https://github.com/python/cpython/pull/26503
https://github.com/python/cpython/commit/60ba0b68470a584103e28958d91e93a6db37ec92 (v3.10.0b2)
https://github.com/python/cpython/commit/ea9327036680acc92d9f89eaf6f6a54d2f8d78d9 (v3.9.6)
https://github.com/python/cpython/commit/f396864ddfe914531b5856d7bf852808ebfc01ae (v3.8.11)
https://github.com/python/cpython/commit/078b146f062d212919d0ba25e34e658a8234aa63 (v3.7.11)
https://github.com/python/cpython/commit/f68d2d69f1da56c2aea1293ecf93ab69a6010ad7 (v3.6.14)
Needs the "Improve the regression test" followup:
https://github.com/python/cpython/commit/98e5a7975d99b58d511f171816ecdfb13d5cca18 (v3.10.0b3)
https://github.com/python/cpython/commit/5df4abd6b033a5f1e48945c6988b45e35e76f647 (v3.9.6)
https://github.com/python/cpython/commit/0389426fa4af4dfc8b1d7f3f291932d928392d8b (3.8 branch)
https://github.com/python/cpython/commit/fee96422e6f0056561cf74fef2012cc066c9db86 (v3.7.11)
https://github.com/python/cpython/commit/1b6f4e5e13ebd1f957b47f7415b53d0869bdbac6 (v3.6.14

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