--- id: CVE-2026-89544 title: |- In the Linux kernel, the following vulnerability has been resolved: SUNRPC: fix gssx_dec_option_array error path bugs Four coupled defects in the gssx XDR option-array decoder make the error paths unsafe: a NULL deref in the caller, a … summary: |- In the Linux kernel, the following vulnerability has been resolved: SUNRPC: fix gssx_dec_option_array error path bugs Four coupled defects in the gssx XDR option-array decoder make the error 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: 0.00612 epssPercentile: 0.47006 scores: nvd: 7.5 cna: 7.5 vendor: 5.5 ingestedAt: '2026-09-14T15:23:07.474Z' --- ## Overview In the Linux kernel, the following vulnerability has been resolved: SUNRPC: fix gssx_dec_option_array error path bugs Four coupled defects in the gssx XDR option-array decoder make the error paths unsafe: a NULL deref in the caller, a refcount leak on the decoded group_info, and a latent use-after-free that the leak fix would otherwise expose. gssx_dec_option_array() sets oa->count = 1 before allocating oa->data. If that allocation fails, -ENOMEM is returned with oa->count == 1 and oa->data == NULL. All other error paths jump to free_oa: which frees oa->data and NULLs it but also leaves oa->count == 1. The caller trusts the count: gssp_accept_sec_context_upcall() gssx_dec_accept_sec_context() gssx_dec_option_array() /* fails, count=1 data=NULL */ data = res.options.data[0].value /* NULL deref */ Independently, free_creds: releases the partially decoded svc_cred with a bare kfree(creds). gssx_dec_linux_creds() installs a groups_alloc() result into creds->cr_group_info; that object is kvmalloc-backed and refcounted, and only put_group_info() reaches kvfree(). A plain kfree(creds) drops the wrapper and leaks the group_info allocation. The natural fix for the leak is to call free_svc_cred(creds) before kfree(creds), but free_svc_cred() invokes put_group_info() on creds->cr_group_info unconditionally when non-NULL. The existing out_free_groups: path in gssx_dec_linux_creds() already called groups_free() on that pointer without clearing it, so once free_svc_cred() is wired in, the subsequent put_group_info() would touch freed memory. Fix all four together: - Move the oa->count = 1 assignment below the oa->data allocation so it is never set when oa->data is NULL. - Reset oa->count to 0 at free_oa: so count and data stay coherent and the caller sees an empty option array. - Call free_svc_cred(creds) before kfree(creds) at free_creds: so the refcounted cr_group_info is released. free_svc_cred() either NULL-guards each field explicitly (cr_group_info has an if() check) or delegates to a helper that is NULL-safe itself (kfree for the string fields, gss_mech_put() which guards with if(gm) at gss_mech_switch.c:342), so it is safe to call on a partially decoded svc_cred where only cr_uid/cr_gid/cr_group_info have been written and everything else is zero from kzalloc. - In gssx_dec_linux_creds()'s out_free_groups: path, release cr_group_info with put_group_info() rather than groups_free() so the teardown matches free_svc_cred()'s refcount-aware path, and clear the pointer so a later free_svc_cred() on the same creds does not release it a second time. ## Remediation Refer to the linked advisories for vendor-supplied fixes and affected version ranges. ## Vendor advisories - **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)