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Fencer Vulns
high 7.5

CVE-2024-37568 json

Authlib has algorithm confusion with asymmetric public keys

published 2024-06-09 2 y ago modified 2026-06-17 4 mo ago also GHSA-5357-c2jx-v7qh , PYSEC-2024-52 , EUVD-2024-0018

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 33%
public exploits
0
none known

Summary

lepture Authlib before 1.3.1 has algorithm confusion with asymmetric public keys. Unless an algorithm is specified in a jwt.decode call, HMAC verification is allowed with any asymmetric public key. (This is similar to CVE-2022-29217 and CVE-2024-33663.)

Patch / fix

  • pypi authlib 1.3.1
  • lepture authlib 1.3.1
  • python-authlib Debian 12 1.2.0-1+deb12u1
  • python-authlib Debian 14, Debian 13 1.3.1-1

debian advisories DEBIAN-CVE-2024-37568

  • python-authlib Ubuntu Pro 22.04 LTS 0.15.5-1ubuntu0.1~esm1
  • python-authlib Ubuntu Pro 24.04 LTS 1.3.0-1ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2024-37568

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • python-Authlib SLE Module for Python 3 15 SP6, openSUSE Leap 15.6 1.3.1-150600.3.3.1

suse advisories SUSE-SU-2024:2064-1

  • python-Authlib openSUSE Tumbleweed 1.7.2-3.1
  • python-Authlib openSUSE Tumbleweed 1.3.1-1.1

opensuse advisories openSUSE-SU-2026:11614-1openSUSE-SU-2024:14035-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2024-37568 updated cvss 5.9

python-authlib: Algorithm confusion when verifying JSON Web Tokens with asymmetric public keys

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.39% chance of exploitation in the next 30 days, higher than 33% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/lepture/authlib/issues/654 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
GitHub 3.1 7.4 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
pypi authlib
<1.3.1
1.3.1

Affected products

  • lepture authlib

Classification

Weakness
  • CWE-284 Improper Access Control
  • CWE-347 Improper Verification of Cryptographic Signature
  • CWE-327 Use of a Broken or Risky Cryptographic Algorithm

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.