CVE-2026-89544

CVE CVE-2026-89544EUVD EUVD-2026-76455Veröffentlicht 2026-09-11T19:44:20.000ZZuletzt geändert 2026-09-13T06:30:43.000ZCVSS 7.5

Was das Advisory beschreibt

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.

Quelle: EUVD (ENISA), im Wortlaut der Meldung.

Produkte, die das Advisory nennt

Diese Angaben stammen aus der Meldung selbst, nicht aus einer Prüfung durch uns.

• Linux — Linux bfa9d86d39a0fe4685f90c3529aa9bd62a9d97a8; 9806c2393cd2ab0a8e7bb9ffae02ce20e3112ec4; patch: 7.3-rc1; patch: 0; 934212a623cbab851848b6de377eb476718c3e4c; 6.7.11 <6.8; patch: 6.18.51; 3cfcfc102a5e57b021b786a755a38935e357797d <5e9a94539b1ec17a89177d952badfd0d844d694a; 5.15.153 <5.16; 6.1.83 <6.2; 5.10.214 <5.11; 5e6013ae2c8d420faea553d363935f65badd32c3; 996997d1fb2126feda550d6adcedcbd94911fc69; 6.8.2 <6.9; 5.4.273 <5.5; patch: 7.2.4; 4.19.311 <4.20; 6.6.23 <6.7; 3cfcfc102a5e57b021b786a755a38935e357797d <f85a83774d7f4e2ac71c0c384df0dfb6f7d0179a; 6.9; b97c37978ca825557d331c9012e0c1ddc0e42364; dd292e884c649f9b1c18af0ec75ca90b390cd044; 3cfcfc102a5e57b021b786a755a38935e357797d <3ff45361e9469e85c0f86b8e7b82c63e50bab8ef; bb336cd8d5ecb69c430ebe3e7bcff68471d93fa8

Die genannten Versionen sind die Angabe der Meldung. Patchlage vergleicht keine Versionsnummern und leitet aus ihnen keine Aussage ab — welche Version installiert ist, muss ein Mensch nachsehen.

Im Produktkatalog geführt

Für diese Produkte kann ein Bestand in Patchlage erfasst werden. Ein Advisory dazu erscheint am Morgen danach im Lagebericht.

• Linux — Linux

Patchlage meldet Treffer und Verdachtsfälle. Zu allem anderen sagt dieses System nichts — weder diese Seite noch der Lagebericht behauptet je, dass ein Bestand sicher ist.