[NEW] [medium] Red Hat Enterprise Linux (libreswan): Multiple vulnerabilities allow Denial of Service

CSIRTS triage

What

Multiple vulnerabilities allow a remote, anonymous attacker to conduct a Denial of Service attack and potentially bypass authentication.

Who is affected

Deployments of Red Hat Enterprise Linux.

Urgency

Remediation is medium urgency due to the potential for service disruption and security risks.

Action

Update to the latest patches for Red Hat Enterprise Linux.

AI-assisted analysis generated from the source advisory — verify against the original.

Details

Source

CERT-Bund (BSI) Security Advisories (DE · national-cert · site)

Severity

medium

Published

2026-07-29

Exploitation

Not in CISA KEV at last sync

Language

Machine-translated to English — verify against the original

Original advisory: https://wid.cert-bund.de/portal/wid/securityadvisory?name=WID-SEC-2026-2518

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

• Low exploitation riskCVE-2026-124130.60% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 45% of all scored CVEs.
• Low exploitation riskCVE-2026-507210.39% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 31% of all scored CVEs.
• Low exploitation riskCVE-2026-507220.35% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 27% of all scored CVEs.

Referenced CVEs

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

• highCVE-2026-50722: IKEv2 Denial of Service via RSA-SHA1 (PKCS#1 RSASSA-PKCS1-v1_5) authentication payloadmsrc
• highCVE-2026-50721: IKEv1 Denial of Service via RSA-SHA1 (PKCS#1 Version 1.5 Encrypted) authentication payloadmsrc
• highCVE-2026-12413: IKEv2 Denial of Service via malformed fragmentationmsrc
• unknownMultiple vulnerabilities in Microsoft Azure Linux (July 10, 2026)cert-fr-avis
• highCVE-2026-50722: Libreswan, via the function RSA_authenticate_hash_signature_pkcs1_1_5_rsa(), did not correctly…nvd
• highCVE-2026-50721: Libreswan, via the function RSA_authenticate_hash_signature_raw_rsa(), did not correctly verif…nvd
• highCVE-2026-12413: An invalidly formatted IKEv2 fragment causes the Libreswan pluto daemon to crash and restart. …nvd

Recent advisories for Red Hat Enterprise

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

• highCVE-2026-18358: A flaw was found in gnome-remote-desktop as shipped in Red Hat Enterprise Linux. When the daem…nvd · 2026-07-31
• medium[NEW] [medium] Red Hat Enterprise Linux (go-billy): Vulnerability allows Denial of Servicecert-bund · 2026-07-31
• high[NEW] [high] Red Hat Enterprise Linux (sssd, glib, c-ares): Multiple vulnerabilitiescert-bund · 2026-07-31
• medium[NEW] [medium] Red Hat Enterprise Linux (python-pillow): Multiple vulnerabilities allow denial of servicecert-bund · 2026-07-31
• medium[NEW] [medium] Red Hat Enterprise Linux (libsolv, aardvark-dns): Multiple vulnerabilitiescert-bund · 2026-07-31
• medium[NEW] [medium] Red Hat Enterprise Linux (freeipmi): Vulnerability allows denial of servicecert-bund · 2026-07-31

More from CERT-Bund (BSI) Security Advisories

• medium[UPDATE] [medium] Linux Kernel: Multiple vulnerabilities allow denial of service2026-07-31
• medium[UPDATE] [medium] Linux Kernel: Multiple vulnerabilities allow Denial of Service2026-07-31
• medium[UPDATE] [medium] Linux Kernel: Multiple vulnerabilities allow denial of service2026-07-31
• medium[UPDATE] [medium] Linux Kernel: Multiple vulnerabilities2026-07-31
• medium[UPDATE] [medium] Linux Kernel: Multiple vulnerabilities allow unspecified attack2026-07-31