Affects widely-used wolfSSL OpenSSL-compat API; could disrupt TLS operations across nginx/haproxy deployments.
CVE-2026-5501
Forged leaf certs accepted via wolfSSL OpenSSL-compat API.
Is CVE-2026-5501 being exploited?
Not confirmed. CVE-2026-5501 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.18% probability of exploitation in the next 30 days.
How severe is CVE-2026-5501?
CVE-2026-5501 is rated High with a CVSS score of 8.6. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-5501?
Not known from our data. No patch reference has been recorded for CVE-2026-5501, which is not the same as no patch existing — a fix may have shipped without a tagged reference, or after this record was written. The vendor advisory is the only authority on whether a fix exists, and mitigations may be available regardless.
What does CVE-2026-5501 affect?
CVE-2026-5501 affects wolfSSL OpenSSL-compat API, nginx (wolfSSL integration), haproxy (wolfSSL integration). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-5501?
Upgrade to patched wolfSSL; fix OpenSSL-compat cert validation.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Impersonation and potential remote code execution in TLS flows through forged certificates.
Patch when possible
- affected<= 5.9.0
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.