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Medium ALAS2023-2026-1680 2 CVEs

Moderate: krb5 security update (Amazon Linux 2023)

Published May 11, 2026 · Updated May 13, 2026

Summary

Package updates are available for Amazon Linux 2023 that fix the following vulnerabilities: CVE-2026-40356: In MIT Kerberos 5 (aka krb5) before 1.22.3, there is an integer underflow and resultant out-of-bounds read if an application calls gss_accept_sec_context() on a system with a NegoEx mechanism registered in /etc/gss/mech. An unauthenticated remote attacker can trigger this, possibly causing the process to terminate in parse_message. CVE-2026-40355: In MIT Kerberos 5 (aka krb5) before 1.22.3, there is a NULL pointer dereference if an application calls gss_accept_sec_context() on a system with a NegoEx mechanism registered in /etc/gss/mech. An unauthenticated remote attacker can trigger this, causing the process to terminate in parse_nego_message.

Fixed packages 15

ReleasePackageFixed in
Amazon Linux · 2023 krb5-debuginfo 0:1.21.3-7.amzn2023.0.1
Amazon Linux · 2023 krb5-debugsource 0:1.21.3-7.amzn2023.0.1
Amazon Linux · 2023 krb5-devel 0:1.21.3-7.amzn2023.0.1
Amazon Linux · 2023 krb5-libs 0:1.21.3-7.amzn2023.0.1
Amazon Linux · 2023 krb5-libs-debuginfo 0:1.21.3-7.amzn2023.0.1
Amazon Linux · 2023 krb5-pkinit 0:1.21.3-7.amzn2023.0.1
Amazon Linux · 2023 krb5-pkinit-debuginfo 0:1.21.3-7.amzn2023.0.1
Amazon Linux · 2023 krb5-server 0:1.21.3-7.amzn2023.0.1
Amazon Linux · 2023 krb5-server-debuginfo 0:1.21.3-7.amzn2023.0.1
Amazon Linux · 2023 krb5-server-ldap 0:1.21.3-7.amzn2023.0.1
Amazon Linux · 2023 krb5-server-ldap-debuginfo 0:1.21.3-7.amzn2023.0.1
Amazon Linux · 2023 krb5-workstation 0:1.21.3-7.amzn2023.0.1
Amazon Linux · 2023 krb5-workstation-debuginfo 0:1.21.3-7.amzn2023.0.1
Amazon Linux · 2023 libkadm5 0:1.21.3-7.amzn2023.0.1
Amazon Linux · 2023 libkadm5-debuginfo 0:1.21.3-7.amzn2023.0.1

Vulnerabilities 2

References

  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-40355.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-40356.html