CVE-2026-54431 | In liboauth2 the Demonstrating Proof-of-Possession (DPoP) ve… | CVSS 5.1 MEDIUM

Description

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

Metadata

CVE ID: CVE-2026-54431
State: PUBLISHED
Assigner: CERT-PL
Reserved: 2026-06-15 13:08 UTC
Published: 2026-07-02 10:30 UTC
Last updated: 2026-07-02 12:16 UTC
Primary CWE: CWE-358
CWE-358 Improperly Implemented Security Check for Standard
Vendor / Product: OpenIDC / liboauth2
Sources: cve.org · NVD

Severity & Metrics

5.1 MEDIUM CVSS 4.0

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

SSVC — CISA Coordinator

Exploitation: none
Automatable: no
Tech. Impact: partial

Affected products (1)

Vendor	Product	Platform	Versions
OpenIDC	liboauth2	—	0 < 2.3.0

Weakness (CWE)

CWE	Source	Description
CWE-358	cna	CWE-358 Improperly Implemented Security Check for Standard

CVSS scores (1)

Score	Severity	Version	Source	Vector
5.1	MEDIUM	4.0	cna	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

References (3)