CVE-2026-5501
CVE-2026-5501 · Improper Certificate Signature Verification in X.509 Chain Validation Allows Forged Leaf Certificates
This page contains facts from public vulnerability sources. Check the original advisory before updating.
wolfSSL_X509_verify_cert in the OpenSSL compatibility layer accepts a certificate chain in which the leaf's signature is not checked, if the attacker supplies an untrusted intermediate with Basic Constraints `CA:FALSE` that is legitimately signed by a trusted root. An attacker who obtains any leaf certificate from a trusted CA (e.g. a free DV cert from Let's Encrypt) can forge a certificate for any subject name with any public key and arbitrary signature bytes, and the function returns `WOLFSSL_SUCCESS` / `X509_V_OK`. The native wolfSSL TLS handshake path (`ProcessPeerCerts`) is not susceptible and the issue is limited to applications using the OpenSSL compatibility API directly, which would include integrations of wolfSSL into nginx and haproxy.
CVSS 8.6 · High · EPSS 0.3%
- Published
- Updated
Stack: system
Affected products and versions
wolfssl
- Versions
- ≥ 0, ≤ 5.9.0: Affected (semver)
No fix published
wolfssl Debian:12
- Versions
- 5.5.4-2
- 5.5.4-2+deb12u1
- 5.5.4-2+deb12u2
- 5.5.4-2+deb12u3
- 5.5.4-2.1
- 5.6.4-1
- 5.6.4-2
- 5.6.6-1
- 5.6.6-1.1
- 5.6.6-1.2
- 5.6.6-1.3
- 5.6.6-1.3~exp1
- 5.7.0-0.1
- 5.7.0-0.2
- 5.7.0-0.3
- 5.7.2-0.1
- 5.7.2-0.2
- 5.7.2-0.3
- 5.7.2-0.4
- 5.8.2-1
- 5.8.2-1.1
- 5.8.2-1.2
- 5.8.4-1
- 5.9.0-0.1
- 5.9.0-0.2
- 5.9.1-0.1
- 5.9.2-1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
wolfssl Debian:13
- Versions
- 5.7.2-0.1
- 5.7.2-0.1+deb13u1
- 5.7.2-0.1+deb13u2
- 5.7.2-0.2
- 5.7.2-0.3
- 5.7.2-0.4
- 5.8.2-1
- 5.8.2-1.1
- 5.8.2-1.2
- 5.8.4-1
- 5.9.0-0.1
- 5.9.0-0.2
- 5.9.1-0.1
- 5.9.2-1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
wolfssl Ubuntu:16.04:LTS
- Versions
- 3.4.8+dfsg-1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
wolfssl Ubuntu:18.04:LTS
- Versions
- 3.10.2+dfsg-2
- 3.12.0+dfsg-1
- 3.12.2+dfsg-1
- 3.13.0+dfsg-1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
wolfssl Ubuntu:20.04:LTS
- Versions
- 4.1.0+dfsg-2
- 4.2.0+dfsg-1
- 4.2.0+dfsg-2
- 4.2.0+dfsg-3
- 4.3.0+dfsg-2
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
wolfssl Ubuntu:22.04:LTS
- Versions
- 4.6.0-3
- 5.0.0-1
- 5.1.1-1
- 5.2.0-1
- 5.2.0-2
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
wolfssl Ubuntu:24.04:LTS
- Versions
- 5.5.4-2
- 5.5.4-2.1
- 5.6.4-2
- 5.6.6-1.2
- 5.6.6-1.3
- 5.6.6-1.3build1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
wolfssl Ubuntu:25.10
- Versions
- 5.7.2-0.1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
wolfssl Ubuntu:26.10
- Versions
- 5.9.1-0.1
- 5.9.2-1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
wolfssl Ubuntu:26.04:LTS
- Versions
- 5.7.2-0.1
- 5.8.2-1.2
- 5.8.4-1
- 5.9.1-0.1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published