GnuTLS is a widely used TLS library; a hostname verification bypass enables broad MITM/eavesdropping risk across systems and distributions.
CVE-2026-88647
Hostname verification bypass in GnuTLS enabling MITM eavesdropping
Is CVE-2026-88647 being exploited?
Not confirmed. CVE-2026-88647 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 0.21% probability of exploitation in the next 30 days.
How severe is CVE-2026-88647?
CVE-2026-88647 is rated Critical with a CVSS score of 9.1. 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-2026-88647?
Not known from our data. No patch reference has been recorded for CVE-2026-88647, 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-2026-88647 affect?
CVE-2026-88647 affects GnuTLS v3.8.13, Applications and OS distributions linking/packing GnuTLS. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-88647?
Remove/replace affected builds, enable certificate pinning, and apply vendor patch when published.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Bypasses hostname verification (Common Name fallback), allowing man-in-the-middle interception or decryption of TLS sessions.
Immediate action required