CVE-2026-88647

CRITICAL

Published Oct 8, 2026 Modified Oct 10, 2026 CWE-297

Description

A hostname verification bypass in GnuTLS v3.8.13 allows attackers to circumvent the Common Name fallback mechanism and eavesdrop on communications via a crafted certificate.

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CVSS v3.1 Score

9.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS — Exploit Prediction

0.0021

Probability of exploitation

0.11%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-297 CWE-297

References

Other References

https://gist.github.com/lkloliver/f98ec3de1a871fdfc02b70b8b9ba7642 https://gitlab.com/gnutls/gnutls/-/issues/1802 https://gitlab.com/gnutls/gnutls/-/issues/1802

Frequently Asked Questions

What is CVE-2026-88647? +

A hostname verification bypass in GnuTLS v3.8.13 allows attackers to circumvent the Common Name fallback mechanism and eavesdrop on communications via a crafted certificate. It has a CVSS v3.1 base score of 9.1 (CRITICAL).

How severe is CVE-2026-88647? +

CVE-2026-88647 has a CVSS v3.1 score of 9.1 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0021, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-88647? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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