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Vulnerability · Published Apr 9, 2026 · Assigned by wolfSSL

CVE-2026-5263URI nameConstraints not enforced in ConfirmNameConstraints()

High 7.0

In plain English

A high-severity improper certificate validation in wolfSSL from wolfSSL. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 8% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)7.0High
Exploit odds (30 days)0.2%top 92.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

URI nameConstraints from constrained intermediate CAs are parsed but not enforced during certificate chain verification in wolfcrypt/src/asn.c. A compromised or malicious sub-CA could issue leaf certificates with URI SAN entries that violate the nameConstraints of the issuing CA, and wolfSSL would accept them as valid.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Alpine:v3.23wolfssl5.9.1-r0ALPINE-CVE-2026-5263
Alpine:v3.24wolfssl5.9.1-r0ALPINE-CVE-2026-5263
Debian:12wolfsslno fix listedDEBIAN-CVE-2026-5263
Debian:13wolfsslno fix listedDEBIAN-CVE-2026-5263
Ubuntu:22.04:LTSwolfsslno fix listedUBUNTU-CVE-2026-5263
Ubuntu:24.04:LTSwolfsslno fix listedUBUNTU-CVE-2026-5263
Ubuntu:25.10wolfsslno fix listedUBUNTU-CVE-2026-5263
Ubuntu:26.04:LTSwolfsslno fix listedUBUNTU-CVE-2026-5263
Ubuntu:26.10wolfsslno fix listedUBUNTU-CVE-2026-5263

Affected products (as reported)

VendorProductVersions
wolfSSL wolfSSL 0 – before 5.9.1

Weakness: CWE-295 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:L/VA:N/SC:H/SI:N/SA:N

References