CVE-2026-54431CWE-358

Improper Data Validation in liboauth2

Medium · published July 2, 2026

CVSS v4.0
5.1
EPSS
0%
Percentile
7.0
In the wild
Unconfirmed
What it is

In liboauth2 the Demonstrating Proof-of-Possession (DPoP) verifier accepts a proof whose JSON Web Key (jwk) header contains private key material. RFC 9449 section 4.3 step 7 requires the verifier to reject such a proof but oauth2_token_verify() function returns success for a malformed DPoP proof that embeds the private Elliptic Curve (EC) key in the header.

This issue was fixed in version 2.3.0

The record
Technical detail
CVSS v4.0
5.1 · MEDIUM
Vector
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
EPSS
0.00178 · 7.0th percentile
Weakness
CWE-358 · Improperly Implemented Security Check for Standard
Published
2026-07-02T10:30Z
EPSS history
Timeline
  • 02 JUL 10:30Z
    Improper Data Validation in liboauth2
    cvelistv5