CVE-2026-6091 | Partial-chain certificate verification may accept chains tha… | CVSS 6.0 MEDIUM

Description

Partial-chain certificate verification may accept chains that terminate at a peer-supplied, untrusted intermediate certificate rather than a trusted anchor. An attacker could present a chain that ends at an intermediate they control and have it accepted as valid. This affects the OpenSSL compatibility certificate-path-building path (wolfSSL_X509_verify_cert / X509_STORE, OPENSSL_EXTRA) when the X509_V_FLAG_PARTIAL_CHAIN verify flag is enabled.

Metadata

CVE ID: CVE-2026-6091
State: PUBLISHED
Assigner: wolfSSL
Reserved: 2026-04-10 16:01 UTC
Published: 2026-06-25 16:46 UTC
Last updated: 2026-06-25 17:58 UTC
Primary CWE: CWE-295
CWE-295 Improper Certificate Validation
Vendor / Product: wolfSSL / wolfSSL
Sources: cve.org · NVD

Severity & Metrics

6.0 MEDIUM CVSS 4.0

CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/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
wolfSSL	wolfSSL	—	5.7.4 ≤ 5.9.1

Weakness (CWE)

CWE	Source	Description
CWE-295	cna	CWE-295 Improper Certificate Validation

CVSS scores (1)

Score	Severity	Version	Source	Vector
6.0	MEDIUM	4.0	cna	CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

References (2)