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High ALSA-2026:46397 4 CVEs

Important: libreswan security update

Published Jul 27, 2026 · Updated Oct 29, 2026

Ecosystem: AlmaLinux

Summary

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.

Fixed packages 1

ReleasePackageFixed in
AlmaLinux · 9 libreswan 4.15-10.el9_8

Vulnerabilities 4

  • High 8.1
    CVE-2026-50721

    IKEv1 Denial of Service via RSA-SHA1 (PKCS#1 Version 1.5 Encrypted) authentication payload

    Libreswan, via the function RSA_authenticate_hash_signature_raw_rsa(), did not correctly verify the length of the authentication hash when the SIG payload of an IKEv1 packet was encoded using PKCS #1 RSA Encryption as per RFC 2313. A remote attacker can use a…

    The Libreswan Project libreswan libreswan libreswan Debian Ubuntu Azure Linux Alpine
  • High 8.1
    CVE-2026-50722

    IKEv2 Denial of Service via RSA-SHA1 (PKCS#1 RSASSA-PKCS1-v1_5) authentication payload

    Libreswan, via the function RSA_authenticate_hash_signature_pkcs1_1_5_rsa(), did not correctly verify the DER encoding of the ASN.1 digest when the IKEv2 AUTH payload was encoded using RSASSA-PKCS1-v1_5 (RFC 8017). A remote attacker can use a variation on the…

    The Libreswan Project libreswan libreswan libreswan Debian Ubuntu Azure Linux Alpine
  • High 7.5
    CVE-2026-12413 Public exploit

    IKEv2 Denial of Service via malformed fragmentation

    An invalidly formatted IKEv2 fragment causes the Libreswan pluto daemon to crash and restart. Continued exploitation would cause a denial of service. The function reassemble_v2_incoming_fragments() would ignore unknown outer payloads but still store these in …

    The Libreswan Project libreswan libreswan libreswan Debian Ubuntu Azure Linux Alpine
  • High 7.5
    CVE-2026-14957

    FIPS mode assertion failure via malicious CERT payload

    In FIPS mode, Libreswan's add_decoded_cert() function calls CERT_ExtractPublicKey() and asserts that the result is not NULL. However, CERT_ExtractPublicKey() returns NULL when public key extraction fails, for example if the RSA exponent is set to 0. A remote …

    The Libreswan Project libreswan libreswan libreswan Debian Ubuntu Azure Linux Alpine

References

  • report
    https://access.redhat.com/security/cve/CVE-2026-12413
  • report
    https://access.redhat.com/security/cve/CVE-2026-14957
  • report
    https://access.redhat.com/security/cve/CVE-2026-50721
  • report
    https://access.redhat.com/security/cve/CVE-2026-50722
  • report
    https://bugzilla.redhat.com/2494147
  • report
    https://bugzilla.redhat.com/2494148
  • report
    https://bugzilla.redhat.com/2494149
  • report
    https://bugzilla.redhat.com/2501764
  • advisory
    https://errata.almalinux.org/9/ALSA-2026-46397.html