Low 3.7Published Oct 13, 2026

CVE-2026-77205Denial of Service via sending bogus X.509 certificates

Updated under an hour ago (2026-10-19 09:30 UTC)

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It affects The Libreswan Project libreswan. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for The Libreswan Project libreswan

Exploited in the last 30 days

Libreswan in FIPS mode has a vulnerability where badly formed received certificates are rejected, but not deleted from the NSS cache. As a result, any real certificates with the same serial number are rejected as well. This can be abused to lock out legitimate peers from connecting. The add_decoded_cert() function missed a call to CERT_DestroyCertificate() due to an incorrect fix for CVE-2026-14957. Sending bogus certificates with new serial numbers could prevent the real certificates with those serial numbers from connecting until the service has restarted.

CVSS: 3.7 LOW (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness (CWE): CWE-772
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: libreswan
NVD analysis: Awaiting Analysis
Record last updated: Oct 16, 2026
First seen by InfoSec Signals: Oct 13, 2026

Affected products

Affected products

The Libreswan Project libreswan libreswan_project:libreswan (from the name)	from 5.3 through 5.3.2; 5.3.3 not affected	CNA record

References

https://libreswan.org/security/CVE-2026-77205/CVE-2026-77205.txtvendor-advisory
https://libreswan.org/security/CVE-2026-77205/patch
https://libreswan.org/security/CVE-2026-14957/CVE-2026-14957.txtrelated

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.