Use After Free Affecting kernel-debug-modules-extra package, versions <0:5.14.0-687.12.1.el9_8


Severity

Recommended
0.0
high
0
10

Based on Rocky Linux security rating.

Threat Intelligence

EPSS
0.01% (3rd percentile)

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  • Snyk IDSNYK-ROCKY9-KERNELDEBUGMODULESEXTRA-17110558
  • published31 May 2026
  • disclosed1 May 2026

Introduced: 1 May 2026

NewCVE-2026-43027  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

Upgrade Rocky-Linux:9 kernel-debug-modules-extra to version 0:5.14.0-687.12.1.el9_8 or higher.
This issue was patched in RLSA-2026:21556.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-debug-modules-extra package and not the kernel-debug-modules-extra package as distributed by Rocky-Linux. See How to fix? for Rocky-Linux:9 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

netfilter: nf_conntrack_helper: pass helper to expect cleanup

nf_conntrack_helper_unregister() calls nf_ct_expect_iterate_destroy() to remove expectations belonging to the helper being unregistered. However, it passes NULL instead of the helper pointer as the data argument, so expect_iter_me() never matches any expectation and all of them survive the cleanup.

After unregister returns, nfnl_cthelper_del() frees the helper object immediately. Subsequent expectation dumps or packet-driven init_conntrack() calls then dereference the freed exp->helper, causing a use-after-free.

Pass the actual helper pointer so expectations referencing it are properly destroyed before the helper object is freed.

BUG: KASAN: slab-use-after-free in string+0x38f/0x430 Read of size 1 at addr ffff888003b14d20 by task poc/103 Call Trace: string+0x38f/0x430 vsnprintf+0x3cc/0x1170 seq_printf+0x17a/0x240 exp_seq_show+0x2e5/0x560 seq_read_iter+0x419/0x1280 proc_reg_read+0x1ac/0x270 vfs_read+0x179/0x930 ksys_read+0xef/0x1c0 Freed by task 103: The buggy address is located 32 bytes inside of freed 192-byte region [ffff888003b14d00, ffff888003b14dc0)

CVSS Base Scores

version 3.1