{"id":"CVE-2026-40356","title":"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","summary":"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 unauthenticat…","severity":"medium","cvss":5.9,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-191"],"vendor":"mit","product":"kerberos_5","affected":["kerberos_5 >= 1.18.0, <= 1.22.2"],"published":"2026-04-28","updated":"2026-07-08","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-40356","references":[{"url":"https://cems.fun/2026/04/27/krb5-two-unauthenticated-network-vulnerabilities.html","label":"cve@mitre.org"},{"url":"https://github.com/krb5/krb5/commit/2e75f0d9362fb979f5fc92829431a590a130929f","label":"cve@mitre.org"},{"url":"https://web.mit.edu/kerberos/advisories/","label":"cve@mitre.org"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40356.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-40356"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2463368"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-40356"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-40356"},{"url":"https://access.redhat.com/errata/RHSA-2026:19145"},{"url":"https://access.redhat.com/errata/RHSA-2026:24685"},{"url":"https://access.redhat.com/errata/RHSA-2026:24686"},{"url":"https://access.redhat.com/errata/RHSA-2026:24683"},{"url":"https://access.redhat.com/errata/RHSA-2026:19357"},{"url":"https://access.redhat.com/errata/RHSA-2026:16799"},{"url":"https://access.redhat.com/errata/RHSA-2026:72502"},{"url":"https://access.redhat.com/errata/RHSA-2026:43692"},{"url":"https://access.redhat.com/errata/RHSA-2026:29197"},{"url":"https://access.redhat.com/errata/RHSA-2026:12220"},{"url":"https://access.redhat.com/errata/RHSA-2026:22634"},{"url":"https://access.redhat.com/errata/RHSA-2026:58981"},{"url":"https://access.redhat.com/errata/RHSA-2026:21275"},{"url":"https://access.redhat.com/errata/RHSA-2026:74674"},{"url":"https://access.redhat.com/errata/RHSA-2026:82322"},{"url":"https://access.redhat.com/errata/RHSA-2026:82304"},{"url":"https://access.redhat.com/errata/RHSA-2026:82354"},{"url":"https://access.redhat.com/errata/RHSA-2026:82372"},{"url":"https://access.redhat.com/errata/RHSA-2026:82347"}],"tags":["nvd","csaf","vex","red-hat"],"epss":0.00604,"epssPercentile":0.48682,"ingestedAt":"2026-07-08T12:51:00.671Z","patched":["enterprise_linux_appstream_v_10","enterprise_linux_appstream_e4s_v_9_2","enterprise_linux_appstream_e4s_v_9_4","enterprise_linux_appstream_eus_v_9_6","enterprise_linux_appstream_v_9","enterprise_linux_baseos_v_10","enterprise_linux_baseos_v_8","enterprise_linux_baseos_e4s_v_9_2","enterprise_linux_baseos_e4s_v_9_4","enterprise_linux_baseos_eus_v_9_6","enterprise_linux_baseos_v_9","cert_manager_support_for_red_hat_openshift_release 1.20","openshift_api_for_data_protection 1.6","discovery 2","hardened_images","insights_proxy 1.5","update_infrastructure 5"],"slug":"CVE-2026-40356","body":"## Overview\n\nIn 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.\n\n## Affected\n\n- `kerberos_5 >= 1.18.0, <= 1.22.2`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **RHSA-2026:19145** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10) · released 2026-05-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:19145)\n- **RHSA-2026:24685** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream E4S (v.9.2), Red Hat Enterprise Linux BaseOS E4S (v.9.2) · released 2026-06-09 · [advisory](https://access.redhat.com/errata/RHSA-2026:24685)\n- **RHSA-2026:24686** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream E4S (v.9.4), Red Hat Enterprise Linux BaseOS E4S (v.9.4) · released 2026-06-09 · [advisory](https://access.redhat.com/errata/RHSA-2026:24686)\n- **RHSA-2026:24683** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v.9.6), Red Hat Enterprise Linux BaseOS EUS (v.9.6) · released 2026-06-09 · [advisory](https://access.redhat.com/errata/RHSA-2026:24683)\n- **RHSA-2026:19357** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9) · released 2026-05-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:19357)\n- **RHSA-2026:16799** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 8) · released 2026-05-13 · [advisory](https://access.redhat.com/errata/RHSA-2026:16799)\n- **RHSA-2026:72502** · Red Hat · fixed in: Cert Manager support for Red Hat OpenShift release 1.20 · released 2026-09-28 · [advisory](https://access.redhat.com/errata/RHSA-2026:72502)\n- **RHSA-2026:43692** · Red Hat · fixed in: OpenShift API for Data Protection 1.6 · released 2026-07-22 · [advisory](https://access.redhat.com/errata/RHSA-2026:43692)\n- **RHSA-2026:29197** · Red Hat · fixed in: Red Hat Discovery 2 · released 2026-06-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:29197)\n- **RHSA-2026:12220** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-04-30 · [advisory](https://access.redhat.com/errata/RHSA-2026:12220)\n- **RHSA-2026:22634** · Red Hat · fixed in: Red Hat Insights proxy 1.5 · released 2026-06-02 · [advisory](https://access.redhat.com/errata/RHSA-2026:22634)\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat OpenShift Container Platform 4 · updated 2026-10-14 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40356.json)\n- **RHSA-2026:82322** · Red Hat · fixed in: Cert Manager support for Red Hat OpenShift release 1.17 · released 2026-10-13 · [advisory](https://access.redhat.com/errata/RHSA-2026:82322)\n- **RHSA-2026:82304** · Red Hat · fixed in: Cert Manager support for Red Hat OpenShift release 1.17 · released 2026-10-13 · [advisory](https://access.redhat.com/errata/RHSA-2026:82304)\n- **RHSA-2026:82354** · Red Hat · fixed in: Cert Manager support for Red Hat OpenShift release 1.18 · released 2026-10-13 · [advisory](https://access.redhat.com/errata/RHSA-2026:82354)\n- **RHSA-2026:82372** · Red Hat · fixed in: Cert Manager support for Red Hat OpenShift release 1.18 · released 2026-10-13 · [advisory](https://access.redhat.com/errata/RHSA-2026:82372)\n- **RHSA-2026:82347** · Red Hat · fixed in: Cert Manager support for Red Hat OpenShift release 1.18 · released 2026-10-13 · [advisory](https://access.redhat.com/errata/RHSA-2026:82347)","depth":"sunlit","depthScore":33,"depthScoreParts":{"impact":32.5,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}