Multiple denial-of-service vulnerabilities in libreswan's IKE implementation allow remote attackers to crash the daemon via specially crafted RSA-SHA1 authentication payloads (CVE-2026-50721, CVE-2026-50722, CVSS 8.1 HIGH) or malformed fragmentation (CVE-2026-12413, CVSS 7.5 HIGH). Affected versions are libreswan prior to 5.3.1, with CVE-2026-12413 specifically affecting versions 4.6 through 5.3. The fix requires upgrading to libreswan version 5.3.1 or later as provided in the Red Hat security update.
Red Hat Product Errata RHSA-2026:46986 - Security Advisory Issued: 2026-07-27 Updated: 2026-07-27 RHSA-2026:46986 - Security Advisory Overview Updated Packages Synopsis Important: libreswan security update Type/Severity Security Advisory: Important Red Hat Lightspeed patch analysis Identify and remediate systems affected by this advisory. View affected systems Topic An update for libreswan is now available for Fast Datapath for Red Hat Enterprise Linux 9. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section. Description Libreswan is an implementation of IPsec and IKE for Linux. IPsec is the Internet Protocol Security and uses strong cryptography to provide both authentication and encryption services. These services allow you to build secure tunnels through untrusted networks such as virtual private network (VPN). Security Fix(es): librenswan: IKEv1 Denial of Service via RSA-SHA1 (PKCS#1 Version 1.5 Encrypted) authentication payload (CVE-2026-50721) librenswan: IKEv2 Denial of Service via RSA-SHA1 (PKCS#1 RSASSA-PKCS1-v1_5) authentication payload (CVE-2026-50722) librenswan: IKEv2 Denial of Service via malformed fragmentation (CVE-2026-12413) libreswan: badly formatted X.509 certificate can cause an assertion failure that crashes the daemon process (CVE-2026-14957) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section. Solution For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Affected Products Red Hat Enterprise Linux Fast Datapath 9 x86_64 Red Hat Enterprise Linux Fast Datapath (for RHEL Server for IBM Power LE) 9 ppc64le Red Hat Enterprise Linux Fast Datapath (for IBM z Systems) 9 s390x Red Hat Enterprise Linux Fast Datapath (for RHEL for ARM 64) 9 aarch64 Fixes BZ - 2494147 - CVE-2026-50721 librenswan: IKEv1 Denial of Service via RSA-SHA1 (PKCS#1 Version 1.5 Encrypted) authentication payload BZ - 2494148 - CVE-2026-50722 librenswan: IKEv2 Denial of Service via RSA-SHA1 (PKCS#1 RSASSA-PKCS1-v1_5) authentication payload BZ - 2494149 - CVE-2026-12413 librenswan: IKEv2 Denial of Service via malformed fragmentation BZ - 2501764 - CVE-2026-14957 libreswan: badly formatted X.509 certificate can cause an assertion failure that crashes the daemon process CVEs CVE-2026-12413 CVE-2026-14957 CVE-2026-50721 CVE-2026-50722 References https://access.redhat.com/security/updates/classification/#important Note: More recent versions of these packages may be available. Click a package name for more details. Red Hat Enterprise Linux Fast Datapath 9 SRPM libreswan-5.3.2-1.el9fdp.src.rpm SHA-256: bdd62561cce47ffb4e63ff00b0a845e9cdee71f37ca8882bb7d195a2c394a1ba x86_64 libreswan-5.3.2-1.el9fdp.x86_64.rpm SHA-256: ec6f2bd7fe7b0087d9f0e2a8a07161b952f89193ccbd594135b643849f79365d libreswan-debuginfo-5.3.2-1.el9fdp.x86_64.rpm SHA-256: eede53c8bcbf538306d32f190443388231dddc5a1dc166462a924986a8bcbf6b libreswan-debugsource-5.3.2-1.el9fdp.x86_64.rpm SHA-256: c82574142e8c757bc6942940520c2db422ab3a5f36a5bac40fd6c37f3373f1d5 Red Hat Enterprise Linux Fast Datapath (for RHEL Server for IBM Power LE) 9 SRPM libreswan-5.3.2-1.el9fdp.src.rpm SHA-256: bdd62561cce47ffb4e63ff00b0a845e9cdee71f37ca8882bb7d195a2c394a1ba ppc64le libreswan-5.3.2-1.el9fdp.ppc64le.rpm SHA-256: 3307aa2d5f9915d706093f5bca4ee2dc56fd65bbb1ada3f131fbe6194a1db6ab libreswan-debuginfo-5.3.2-1.el9fdp.ppc64le.rpm SHA-256: 9cbaa1d08cb43435dd344e5a32d58a536682b3bb79fdaf3c9de13a613c18c677 libreswan-debugsource-5.3.2-1.el9fdp.ppc64le.rpm SHA-256: ed4591330ff744db1f2ffba55aa526d9240bd3c8f8b3e380ac8ebe747fad9c10 Red Hat Enterprise Linux Fast Datapath (for IBM z Systems) 9 SRPM libreswan-5.3.2-1.el9fdp.src.rpm SHA-256: bdd62561cce47ffb4e63ff00b0a845e9cdee71f37ca8882bb7d195a2c394a1ba s390x libreswan-5.3.2-1.el9fdp.s390x.rpm SHA-256: ff759d329c50186685aa147c657cea0e2bc739fc0524eb96d247569ee111ed72 libreswan-debuginfo-5.3.2-1.el9fdp.s390x.rpm SHA-256: ef447f03cf05fb9683b9a1dc29b11d745256ee82e2263f49a9cf014f0b1625d3 libreswan-debugsource-5.3.2-1.el9fdp.s390x.rpm SHA-256: 5a7ac6fade3068439fe8c21df9c12f1a5e43eb6b33617bf449b861badc5b3d4f Red Hat Enterprise Linux Fast Datapath (for RHEL for ARM 64) 9 SRPM libreswan-5.3.2-1.el9fdp.src.rpm SHA-256: bdd62561cce47ffb4e63ff00b0a845e9cdee71f37ca8882bb7d195a2c394a1ba aarch64 libreswan-5.3.2-1.el9fdp.aarch64.rpm SHA-256: 65054d1d5429a504b0881981b1e34e5986d695e9c0301ebb7d6dab89507fb5ef libreswan-debuginfo-5.3.2-1.el9fdp.aarch64.rpm SHA-256: 9b523815c38820a3dcdf59c10e524402cfcbb2ea902af773bcd9f11441878787 libreswan-debugsource-5.3.2-1.el9fdp.aarch64.rpm SHA-256: 49967dd228712e728d11352e734a67d99b53573d39b1765232e1aef11b63f194 The Red Hat security contact is secalert@redhat.com . More contact details at https://access.redhat.com/security/team/contact/ .