CVE-2026-77205

Denial of Service via sending bogus X.509 certificates

CVSS score

3.7

EPSS probability

%0.2

Risk score

0.0

Published

1 d ago

Overview Public Exploits (0)Newsroom Vulnerability Timeline

Official patch verified

Etkilenen ürün ve sürüm için yayımlanan güvenlik güncellemesini uygulayın.

Impact on My Inventory

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Vulnerability description

CVE AI research

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DayBreach AI Explanation

Verified against sources

Libreswan Denial of Service Vulnerability in FIPS Mode

Sources read

Source agreement

Tam uyum

Evidence confidence

%55

Short explanation

Libreswan in FIPS mode contains a denial of service vulnerability because badly formed received certificates are not deleted from the NSS cache, which can be abused to prevent legitimate peers from connecting.

Why does it matter?

The vulnerability targets certificate caching mechanisms during authentication, leading to dropped legitimate connections and disrupting service availability.

What should be done?

Follow the vendor security advisory
Upgrade to the unaffected version where applicable

Chain of evidence and sources2 verified claims

Libreswan FIPS modundayken, hatalı biçimlendirilmiş sertifikalar NSS önbelleğinden silinmez ve hizmet engelleme durumuna neden olur.

S0 · daybreach-canonical S1 · cvelist

CVE-2026-77205 zafiyeti, CVE-2026-14957 için yapılan hatalı bir düzeltmeden kaynaklanan eksik CERT_DestroyCertificate() çağrısından kaynaklanmaktadır.

S0 · daybreach-canonical S1 · cvelist

Show the technical text from the sources

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

CWE: CWE-772

Explanation produced with the local gemini-flash-lite-latest model. Numerical metrics and the KEV, patch and exploit statuses are not determined by AI.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-77205 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

ID	VENDOR	PRODUCT	ACTION
1	The Libreswan Project	libreswan	View

Total affected vendors: 1|Products: 1

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCORE	VERSION	SEVERITY	VECTOR	SOURCE
3.7	CVSS V31	LOW	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L	NVD
3.7	CVSS V3_1	LOW	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L	CVE CNA

Patch and Remediation Guide

Solution & Remediation Advisory

Patch verified

2 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

cvelist

Libreswan CVE-2026-77205 Patches

Open source

reference

Libreswan CVE-2026-77205 Patches

Open source

Confirm the affected product and version against the source evidence above.

Restrict access to internet-facing services and apply network segmentation.

Apply the official update named in the evidence only to the matching product and version.

Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-77205 is associated with the following CWEs:

CWE-772: Common Weakness Enumeration Entry CWE-772

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.

CAPEC-66: SQL Injection CAPEC-126: Path Traversal CAPEC-28: OS Command Injection

Attack Vector and Accessibility

ExposureAğ üzerinden

PermissionsGerekmiyor

UserGerekmiyor

Official Sources and Advisories

Libreswan Security Advisory CVE-2026-77205vendor-advisory Libreswan CVE-2026-77205 Patchespatch Related: CVE-2026-14957 (incorrect fix being corrected)vendor-advisory

CVSS Vector Radar Chart

3.7 / 10

Vulnerability Scoring Details

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

Attack VectorNetwork

Attack ComplexityHigh

Privileges RequiredNone required

User InteractionNone required

Confidentiality (Gizlilik)High

Integrity (Bütünlük)None

Availability (Erişilebilirlik)Low

Yama doğrulandı

2 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

Follow the vendor

The Libreswan Project

Weakness Type (CWE & CAPEC)

CWE-772

Similar Vulnerabilities

7.5

CVE-2026-77206

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