Multiple denial-of-service vulnerabilities in libreswan, including attacks via RSA-SHA1 authentication payloads in IKEv1/IKEv2 (CVE-2026-50721, CVSS 8.1; CVE-2026-50722, CVSS 8.1) and via malformed IKEv2 fragmentation (CVE-2026-12413, CVSS 7.5), allow remote attackers to crash the IPsec service. Affected versions are libreswan prior to 5.3.1, with CVE-2026-12413 specifically affecting versions 4.6 through 5.3. The fix is to upgrade libreswan to version 5.3.1.
Red Hat Product Errata RHSA-2026:55449 - Security Advisory Issued: 2026-08-17 Updated: 2026-08-17 RHSA-2026:55449 - 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 Red Hat Enterprise Linux 10.0 Extended Update Support. 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 for x86_64 - Extended Update Support 10.0 x86_64 Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 10.0 s390x Red Hat Enterprise Linux for Power, little endian - Extended Update Support 10.0 ppc64le Red Hat Enterprise Linux for ARM 64 - Extended Update Support 10.0 aarch64 Red Hat Enterprise Linux for ARM 64 - 4 years of updates 10.0 aarch64 Red Hat Enterprise Linux for IBM z Systems - 4 years of updates 10.0 s390x Red Hat Enterprise Linux for Power, little endian - 4 years of support 10.0 ppc64le Red Hat Enterprise Linux for x86_64 - 4 years of updates 10.0 x86_64 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 for x86_64 - Extended Update Support 10.0 SRPM libreswan-5.2-1.el10_0.5.src.rpm SHA-256: 992cc28fb1945358c59144cec04bfebfc3766d902ec38e14e346e2682f926c4c x86_64 libreswan-5.2-1.el10_0.5.x86_64.rpm SHA-256: 29851fd315880bfe66063767c123320022f14789f3dff2543cf9663ce2daa2b6 libreswan-debuginfo-5.2-1.el10_0.5.x86_64.rpm SHA-256: d72a565c03b852c9012c89219e98a45b87d427899ac994baa96cf570819c69ab libreswan-debugsource-5.2-1.el10_0.5.x86_64.rpm SHA-256: ebc9972ff3da3a5a25de9835e52ba152a9cdcbe168dd8b2e133d001bb835d1a2 Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 10.0 SRPM libreswan-5.2-1.el10_0.5.src.rpm SHA-256: 992cc28fb1945358c59144cec04bfebfc3766d902ec38e14e346e2682f926c4c s390x libreswan-5.2-1.el10_0.5.s390x.rpm SHA-256: f48f5a2f735b5a122334618ae3d8ad328edc80e034cfbb57a1c6bf6f8315aef3 libreswan-debuginfo-5.2-1.el10_0.5.s390x.rpm SHA-256: 5ca59b8c9f4e5a1bf72320bf68c1e579734f1dccce1beec7d59b4594fd2b63ef libreswan-debugsource-5.2-1.el10_0.5.s390x.rpm SHA-256: 976381bdf6eae51b7995f8aa00107450b03f49423064c10e836cb6ade447439f Red Hat Enterprise Linux for Power, little endian - Extended Update Support 10.0 SRPM libreswan-5.2-1.el10_0.5.src.rpm SHA-256: 992cc28fb1945358c59144cec04bfebfc3766d902ec38e14e346e2682f926c4c ppc64le libreswan-5.2-1.el10_0.5.ppc64le.rpm SHA-256: f943e2913807cc868fefd6ab855b673691511d1907a40112c40e5925644e9c56 libreswan-debuginfo-5.2-1.el10_0.5.ppc64le.rpm SHA-256: a98ee2f6e954754635a0e19293ec888e69aa808227571bbeee02c80d997f382c libreswan-debugsource-5.2-1.el10_0.5.ppc64le.rpm SHA-256: c69509fc13d145d65f2ed6d84d6b406626dc00a4b1b4c87a160716fa111efc21 Red Hat Enterprise Linux for ARM 64 - Extended Update Support 10.0 SRPM libreswan-5.2-1.el10_0.5.src.rpm SHA-256: 992cc28fb1945358c59144cec04bfebfc3766d902ec38e14e346e2682f926c4c aarch64 libreswan-5.2-1.el10_0.5.aarch64.rpm SHA-256: 7407f90a405f845dc541e69dbdace01b9cf04169694d7c722d1f77bf215b5405 libreswan-debuginfo-5.2-1.el10_0.5.aarch64.rpm SHA-256: 11adf60f4d16c48ad42756371998558e2866bf852f3377d92c6783d9f472e331 libreswan-debugsource-5.2-1.el10_0.5.aarch64.rpm SHA-256: 81169974f1279bc34b9bdffd8a010fa43d6a2b7372f5aaf9101cb73cb238f30d Red Hat Enterprise Linux for ARM 64 - 4 years of updates 10.0 SRPM libreswan-5.2-1.el10_0.5.src.rpm SHA-256: 992cc28fb1945358c59144cec04bfebfc3766d902ec38e14e346e2682f926c4c aarch64 libreswan-5.2-1.el10_0.5.aarch64.rpm SHA-256: 7407f90a405f845dc541e69dbdace01b9cf04169694d7c722d1f77bf215b5405 libreswan-debuginfo-5.2-1.el10_0.5.aarch64.rpm SHA-256: 11adf60f4d16c48ad42756371998558e2866bf852f3377d92c6783d9f472e331 libreswan-debugsource-5.2-1.el10_0.5.aarch64.rpm SHA-256: 81169974f1279bc34b9bdffd8a010fa43d6a2b7372f5aaf9101cb73cb238f30d Red Hat Enterprise Linux for IBM z Systems - 4 years of updates 10.0 SRPM libreswan-5.2-1.el10_0.5.src.rpm SHA-256: 992cc28fb1945358c59144cec04bfebfc3766d902ec38e14e346e2682f926c4c s390x libreswan-5.2-1.el10_0.5.s390x.rpm SHA-256: f48f5a2f735b5a122334618ae3d8ad328edc80e034cfbb57a1c6bf6f8315aef3 libreswan-debuginfo-5.2-1.el10_0.5.s390x.rpm SHA-256: 5ca59b8c9f4e5a1bf72320bf68c1e579734f1dccce1beec7d59b4594fd2b63ef libreswan-debugsource-5.2-1.el10_0.5.s390x.rpm SHA-256: 976381bdf6eae51b7995f8aa00107450b03f49423064c10e836cb6ade447439f Red Hat Enterprise Linux for Power, little endian - 4 years of support 10.0 SRPM libreswan-5.2-1.el10_0.5.src.rpm SHA-256: 992cc28fb1945358c59144cec04bfebfc3766d902ec38e14e346e2682f926c4c ppc64le libreswan-5.2-1.el10_0.5.ppc64le.rpm SHA-256: f943e2913807cc868fefd6ab855b673691511d1907a40112c40e5925644e9c56 libreswan-debuginfo-5.2-1.el10_0.5.ppc64le.rpm SHA-256: a98ee2f6e954754635a0e19293ec888e69aa808227571bbeee02c80d997f382c libreswan-debugsource-5.2-1.el10_0.5.ppc64le.rpm SHA-256: c69509fc13d145d65f2ed6d84d6b406626dc00a4b1b4c87a160716fa111efc21 Red Hat Enterprise Linux for x86_64 - 4 years of updates 10.0 SRPM libreswan-5.2-1.el10_0.5.src.rpm SHA-256: 992cc28fb1945358c59144cec04bfebfc3766d902ec38e14e346e2682f926c4c x86_64 libreswan-5.2-1.el10_0.5.x86_64.rpm SHA-256: 29851fd315880bfe66063767c123320022f14789f3dff2543cf9663ce2daa2b6 libreswan-debuginfo-5.2-1.el10_0.5.x86_64.rpm SHA-256: d72a565c03b852c9012c89219e98a45b87d427899ac994baa96cf570819c69ab libreswan-debugsource-5.2-1.el10_0.5.x86_64.rpm SHA-256: ebc9972ff3da3a5a25de9835e52ba152a9cdcbe168dd8b2e133d001bb835d1a2 The Red Hat security contact is secalert@redhat.com . 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