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Fencer Vulns
critical 9.1

CVE-2021-41945 json

Improper Input Validation in httpx

published 2022-04-28 4 y ago modified 2026-07-09 4 mo ago also GHSA-h8pj-cxx2-jfg2 , PYSEC-2022-183 , EUVD-2022-0122

cvss
9.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.1%
EPSS 2.1% chance of exploitation in 30 days, percentile 81%
public exploits
0
none known

Summary

Encode OSS httpx < 0.23.0 is affected by improper input validation in `httpx.URL`, `httpx.Client` and some functions using `httpx.URL.copy_with`.

Patch / fix

  • pypi httpx 0.20.0, 0.23.0
  • encode httpx 0.23.0
  • httpx Debian 14, Debian 13, Debian 12 0.23.0-1

debian advisories DEBIAN-CVE-2021-41945

  • python-httpx openSUSE Tumbleweed 0.28.1-2.1

opensuse advisories openSUSE-SU-2025:14664-1

  • python-httpx Arch Linux 0.22.0-2

arch linux advisories AVG-2718

Exploit prediction

2.12% chance of exploitation in the next 30 days, higher than 81% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • gist.github.com https://gist.github.com/lebr0nli/4edb76bbd3b5ff993cf44f2fbce5e571 referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/encode/httpx/discussions/1831 referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/encode/httpx/issues/2184 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
NVD 2.0 6.4 AV:N/AC:L/Au:N/C:P/I:P/A:N
GitHub 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
pypi httpx
<0.23.0
<0.20.0
0.23.0
0.20.0

Classification

Weakness
  • CWE-20 Improper Input Validation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.