CVE-2026-77205
Denial of Service via sending bogus X.509 certificates
Description
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.
INFO
Published Date :
Oct. 13, 2026, 10:18 p.m.
Last Modified :
Oct. 13, 2026, 10:18 p.m.
Remotely Exploit :
Yes !
Source :
d42dc95b-23f1-4e06-9076-20753a0fb0df
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | LOW | d42dc95b-23f1-4e06-9076-20753a0fb0df | ||||
| CVSS 3.1 | LOW | MITRE-CVE |
Solution
- Apply the correct fix for CVE-2026-14957.
- Ensure badly formed certificates are deleted from the NSS cache.
- Restart the service after applying updates.
- Validate certificate handling logic.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-77205.
| URL | Resource |
|---|---|
| https://libreswan.org/security/CVE-2026-14957/CVE-2026-14957.txt | |
| https://libreswan.org/security/CVE-2026-77205/ | |
| https://libreswan.org/security/CVE-2026-77205/CVE-2026-77205.txt |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-77205 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-77205
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-77205 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-77205 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by d42dc95b-23f1-4e06-9076-20753a0fb0df
Oct. 13, 2026
Action Type Old Value New Value Added Description 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. Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L Added CWE CWE-772 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/77xxx/CVE-2026-77205.json">CVE-2026-77205</a> Added Reference https://libreswan.org/security/CVE-2026-14957/CVE-2026-14957.txt Added Reference https://libreswan.org/security/CVE-2026-77205/ Added Reference https://libreswan.org/security/CVE-2026-77205/CVE-2026-77205.txt