{"id":"CVE-2026-40355","title":"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","summary":"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 trig…","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-476"],"vendor":"mit","product":"kerberos_5","affected":["kerberos_5 >= 1.18.0, <= 1.22.2"],"patched":["enterprise_linux_appstream_v_10","enterprise_linux_appstream_v_9","enterprise_linux_baseos_v_10","enterprise_linux_baseos_v_8","enterprise_linux_baseos_v_9","cert_manager_support_for_red_hat_openshift_release 1.20","discovery 2","hardened_images","insights_proxy 1.5","update_infrastructure 5"],"published":"2026-04-28","updated":"2026-10-15","sourceUpdated":"2026-10-15T02:19:22.700","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-40355","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://cems.fun/2026/04/27/krb5-two-unauthenticated-network-vulnerabilities.html","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-019113.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-082556.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-457936.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40355.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-40355"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2463370"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-40355"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-40355"},{"url":"https://access.redhat.com/errata/RHSA-2026:19145"},{"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-2026:29197"},{"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-2026:82322"},{"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","cve.org","exploit-available","csaf","vex","red-hat"],"epss":0.00645,"epssPercentile":0.50724,"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"no","technicalImpact":"partial","timestamp":"2026-04-28T12:53:15.785781Z"},"ingestedAt":"2026-07-08T12:51:00.642Z","slug":"CVE-2026-40355","body":"## Overview\n\nIn 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.\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-2026:19357** · 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-2026:29197** · 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- **RHSA-2026:58981** · Red Hat · fixed in: Red Hat Update Infrastructure 5 · released 2026-08-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:58981)\n- **RHSA-2026:21275** · Red Hat · fixed in: Red Hat Update Infrastructure 5 · released 2026-05-27 · [advisory](https://access.redhat.com/errata/RHSA-2026:21275)\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-2026-40355.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":"twilight","depthScore":45,"depthScoreParts":{"impact":32.5,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[{"seq":5173,"id":"CVE-2026-40355","ts":1788887251459,"field":"exploit_available","old":"false","new":"true"},{"seq":4056,"id":"CVE-2026-40355","ts":1788886367395,"field":"exploit_available","old":"true","new":"false"},{"seq":2847,"id":"CVE-2026-40355","ts":1788883034008,"field":"exploit_available","old":"false","new":"true"},{"seq":1876,"id":"CVE-2026-40355","ts":1788882436916,"field":"exploit_available","old":"true","new":"false"},{"seq":313,"id":"CVE-2026-40355","ts":1788881649920,"field":"exploit_available","old":"false","new":"true"}]}