{"id":"CVE-2026-89544","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: fix gssx_dec_option_array error path bugs\n\nFour coupled defects in the gssx XDR option-array decoder make the\nerror paths unsafe: a NULL deref in the caller, a …","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: fix gssx_dec_option_array error path bugs\n\nFour coupled defects in the gssx XDR option-array decoder make the\nerror paths unsafe: a NULL deref in the caller, a …","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-476"],"vendor":"Linux","product":"Linux","affected":["Linux >= 3cfcfc102a5e57b021b786a755a38935e357797d < fb30241f7ccace372ee83017891549f23a715581","Linux >= 3cfcfc102a5e57b021b786a755a38935e357797d < 3ff45361e9469e85c0f86b8e7b82c63e50bab8ef","Linux >= 3cfcfc102a5e57b021b786a755a38935e357797d < f85a83774d7f4e2ac71c0c384df0dfb6f7d0179a","Linux >= 3cfcfc102a5e57b021b786a755a38935e357797d < 5e9a94539b1ec17a89177d952badfd0d844d694a","Linux b97c37978ca825557d331c9012e0c1ddc0e42364","Linux bfa9d86d39a0fe4685f90c3529aa9bd62a9d97a8","Linux bb336cd8d5ecb69c430ebe3e7bcff68471d93fa8","Linux dd292e884c649f9b1c18af0ec75ca90b390cd044","Linux 934212a623cbab851848b6de377eb476718c3e4c","Linux 5e6013ae2c8d420faea553d363935f65badd32c3","Linux 9806c2393cd2ab0a8e7bb9ffae02ce20e3112ec4","Linux 996997d1fb2126feda550d6adcedcbd94911fc69","Linux >= 4.19.311 < 4.20","Linux >= 5.4.273 < 5.5","Linux >= 5.10.214 < 5.11","Linux >= 5.15.153 < 5.16","Linux >= 6.1.83 < 6.2","Linux >= 6.6.23 < 6.7","Linux >= 6.7.11 < 6.8","Linux >= 6.8.2 < 6.9","Linux 6.9"],"published":"2026-09-11","updated":"2026-09-21","sourceUpdated":"2026-09-21T14:17:22.970","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-89544","references":[{"url":"https://git.kernel.org/stable/c/3ff45361e9469e85c0f86b8e7b82c63e50bab8ef","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5e9a94539b1ec17a89177d952badfd0d844d694a","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f85a83774d7f4e2ac71c0c384df0dfb6f7d0179a","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/fb30241f7ccace372ee83017891549f23a715581","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89544.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89544"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532048"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89544"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89544"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89544.mbox"}],"tags":["nvd","cve.org","csaf","vex","red-hat","score-dispute"],"epss":0.00586,"epssPercentile":0.46722,"scores":{"nvd":7.5,"cna":7.5,"vendor":5.5},"ingestedAt":"2026-09-14T15:23:07.474Z","slug":"CVE-2026-89544","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: fix gssx_dec_option_array error path bugs\n\nFour coupled defects in the gssx XDR option-array decoder make the\nerror paths unsafe: a NULL deref in the caller, a refcount leak on\nthe decoded group_info, and a latent use-after-free that the leak\nfix would otherwise expose.\n\ngssx_dec_option_array() sets oa->count = 1 before allocating\noa->data.  If that allocation fails, -ENOMEM is returned with\noa->count == 1 and oa->data == NULL.  All other error paths jump\nto free_oa: which frees oa->data and NULLs it but also leaves\noa->count == 1.  The caller trusts the count:\n\n    gssp_accept_sec_context_upcall()\n      gssx_dec_accept_sec_context()\n        gssx_dec_option_array()        /* fails, count=1 data=NULL */\n      data = res.options.data[0].value /* NULL deref */\n\nIndependently, free_creds: releases the partially decoded svc_cred\nwith a bare kfree(creds).  gssx_dec_linux_creds() installs a\ngroups_alloc() result into creds->cr_group_info; that object is\nkvmalloc-backed and refcounted, and only put_group_info() reaches\nkvfree().  A plain kfree(creds) drops the wrapper and leaks the\ngroup_info allocation.\n\nThe natural fix for the leak is to call free_svc_cred(creds) before\nkfree(creds), but free_svc_cred() invokes put_group_info() on\ncreds->cr_group_info unconditionally when non-NULL.  The existing\nout_free_groups: path in gssx_dec_linux_creds() already called\ngroups_free() on that pointer without clearing it, so once\nfree_svc_cred() is wired in, the subsequent put_group_info() would\ntouch freed memory.\n\nFix all four together:\n\n  - Move the oa->count = 1 assignment below the oa->data allocation\n    so it is never set when oa->data is NULL.\n  - Reset oa->count to 0 at free_oa: so count and data stay\n    coherent and the caller sees an empty option array.\n  - Call free_svc_cred(creds) before kfree(creds) at free_creds:\n    so the refcounted cr_group_info is released.  free_svc_cred()\n    either NULL-guards each field explicitly (cr_group_info has\n    an if() check) or delegates to a helper that is NULL-safe\n    itself (kfree for the string fields, gss_mech_put() which\n    guards with if(gm) at gss_mech_switch.c:342), so it is safe\n    to call on a partially decoded svc_cred where only\n    cr_uid/cr_gid/cr_group_info have been written and everything\n    else is zero from kzalloc.\n  - In gssx_dec_linux_creds()'s out_free_groups: path, release\n    cr_group_info with put_group_info() rather than groups_free()\n    so the teardown matches free_svc_cred()'s refcount-aware path,\n    and clear the pointer so a later free_svc_cred() on the same\n    creds does not release it a second time.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-09-14 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89544.json)","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":208391,"id":"CVE-2026-89544","ts":1789997916160,"field":"cvss","old":"5.5","new":"7.5"},{"seq":208390,"id":"CVE-2026-89544","ts":1789997916160,"field":"severity","old":"medium","new":"high"},{"seq":204226,"id":"CVE-2026-89544","ts":1789490240384,"field":"cvss","old":"5.9","new":"5.5"},{"seq":203019,"id":"CVE-2026-89544","ts":1789403733371,"field":"cvss","old":"7.5","new":"5.9"},{"seq":203018,"id":"CVE-2026-89544","ts":1789403733371,"field":"severity","old":"high","new":"medium"},{"seq":197943,"id":"CVE-2026-89544","ts":1789384321067,"field":"cvss","old":"5.9","new":"7.5"},{"seq":197942,"id":"CVE-2026-89544","ts":1789384321067,"field":"severity","old":"medium","new":"high"},{"seq":183748,"id":"CVE-2026-89544","ts":1789356677222,"field":"cvss","old":"7.5","new":"5.9"},{"seq":183747,"id":"CVE-2026-89544","ts":1789356677222,"field":"severity","old":"high","new":"medium"},{"seq":153344,"id":"CVE-2026-89544","ts":1789285350129,"field":"cvss","old":null,"new":"7.5"},{"seq":153343,"id":"CVE-2026-89544","ts":1789285350129,"field":"severity","old":"none","new":"high"},{"seq":109590,"id":"CVE-2026-89544","ts":1789183732534,"field":"cvss","old":null,"new":"5.9"},{"seq":109589,"id":"CVE-2026-89544","ts":1789183732534,"field":"severity","old":"none","new":"medium"}]}