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Vulnerabilities

Vulnerability · CVE-2026-77205

Libreswan in FIPS mode has a vulnerability where badly formed received certificates are rejected, but not deleted from the NSS cache.

Published Oct 13, 2026 · catalog updated Oct 13, 2026 · Libreswan in FIPS mode

Check if you run it

No confirmed exploitation is on record for CVE-2026-77205. EPSS is 0.18%. Act only if a listed version of Libreswan in FIPS mode is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Libreswan in FIPS mode).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Low3.7
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.18%
Remediation
Advisory link
Affected products
See sources for product scope

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.

No affected version ranges are stored yet. Use the vendor advisory before you decide this record does not apply.

How to fix CVE-2026-77205

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-77205. EPSS is 0.18%. Act only if a listed version of Libreswan in FIPS mode is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-772: Missing Release of Resource after Effective Lifetime. EPSS 0.18%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 13, 2026 · Catalog

    Detected

    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-2026-1495

Sources

  • CVE.orgVulnerability recordCVE-2026-77205

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-77205

    30-day exploitation probability 0.2%

    first.org
  • NIST NVDVulnerability recordCVE-2026-77205

    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 connecti

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.