---
id: CVE-2026-77205
title: >-
  Libreswan in FIPS mode has a vulnerability where badly formed received
  certificates are rejected, but not deleted from the NSS cache
summary: >-
  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…
severity: low
cvss: 3.7
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L'
cwe:
  - CWE-772
  - CWE-459
vendor: Red Hat
product: Red Hat Enterprise Linux 10
affected:
  - fast_datapath_for_rhel 9
  - enterprise_linux 10
  - openshift_container_platform 4
published: '2026-10-13'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T19:55:59.740'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-77205'
references:
  - url: 'https://libreswan.org/security/CVE-2026-14957/CVE-2026-14957.txt'
    label: d42dc95b-23f1-4e06-9076-20753a0fb0df
  - url: 'https://libreswan.org/security/CVE-2026-77205/'
    label: d42dc95b-23f1-4e06-9076-20753a0fb0df
  - url: 'https://libreswan.org/security/CVE-2026-77205/CVE-2026-77205.txt'
    label: d42dc95b-23f1-4e06-9076-20753a0fb0df
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-77205.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-77205'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2550255'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-77205'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-77205'
  - url: >-
      https://libreswan.org/security/CVE-2026-77205/libreswan-5.3-CVE-2026-77205.patch
tags:
  - nvd
  - csaf
  - vex
  - red-hat
  - cve.org
epss: 0.00183
epssPercentile: 0.0782
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-16T15:14:28.040688Z'
ingestedAt: '2026-10-13T23:03:54.749Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Low · affected: Fast Datapath for RHEL 9, Red Hat Enterprise Linux 10, Red Hat OpenShift Container Platform 4 · no fix planned: Fast Datapath for RHEL 9, Red Hat Enterprise Linux 10, Red Hat OpenShift Container Platform 4 · updated 2026-10-13 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-77205.json)