CVE-2026-89544SUNRPC: fix gssx_dec_option_array error path bugs

Description

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.

Timeline

Scores

EPSS (exploitation in 30 days)

0.72% · top 45% of all CVEs (12 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: yes · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.

Affected products

• Linux · Linux

  • affected bb336cd8d5ecb69c430ebe3e7bcff68471d93fa8 – < ac86b45bb978cd4fdbcaaca82dd0f2337f8e310c
  • affected dd292e884c649f9b1c18af0ec75ca90b390cd044 – < 3473139d15d67e2fd737cf0613082adb5499362f
  • affected 934212a623cbab851848b6de377eb476718c3e4c – < 993a9012e68b8667a0a9b316fd718680c7e008a0
  • affected 5e6013ae2c8d420faea553d363935f65badd32c3 – < 8c56a46db3b7523f13e167c3e2c6e3c47a87dcb3
  • affected 3cfcfc102a5e57b021b786a755a38935e357797d – < fb30241f7ccace372ee83017891549f23a715581
  • affected 3cfcfc102a5e57b021b786a755a38935e357797d – < 3ff45361e9469e85c0f86b8e7b82c63e50bab8ef
  • affected 3cfcfc102a5e57b021b786a755a38935e357797d – < f85a83774d7f4e2ac71c0c384df0dfb6f7d0179a
  • affected 3cfcfc102a5e57b021b786a755a38935e357797d – < 5e9a94539b1ec17a89177d952badfd0d844d694a
  • affected b97c37978ca825557d331c9012e0c1ddc0e42364
  • affected bfa9d86d39a0fe4685f90c3529aa9bd62a9d97a8
  • affected 9806c2393cd2ab0a8e7bb9ffae02ce20e3112ec4
  • affected 996997d1fb2126feda550d6adcedcbd94911fc69
  • affected 5.10.214 – < 5.10.273
  • affected 5.15.153 – < 5.15.224
  • affected 6.1.83 – < 6.1.191
  • affected 6.6.23 – < 6.6.160
  • affected 4.19.311 – < 4.20
  • affected 5.4.273 – < 5.5
  • affected 6.7.11 – < 6.8
  • affected 6.8.2 – < 6.9

• Linux · Linux

  • affected 6.9
  • unaffected < 6.9
  • unaffected 5.10.273 – ≤ 5.10.*
  • unaffected 5.15.224 – ≤ 5.15.*
  • unaffected 6.1.191 – ≤ 6.1.*
  • unaffected 6.6.160 – ≤ 6.6.*
  • unaffected 6.12.111 – ≤ 6.12.*
  • unaffected 6.18.51 – ≤ 6.18.*
  • unaffected 7.2.4 – ≤ 7.2.*
  • unaffected 7.3 – ≤ *

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• EUVD EUVD-2026-76455 (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-89544](https://cveledger.app/badge/CVE-2026-89544.svg)](https://cveledger.app/cve/CVE-2026-89544)

Record last updated 30 Oct 2026, 12:32 UTC.