CVE-2026-43027
Description
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)
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| sles | affected | | |
| rhel | 9 | fixed | |
| debian | bookworm | fixed | 6.1.170-1 |
| debian | forky | fixed | 6.19.12-1 |
| debian | sid | fixed | 6.19.12-1 |
| debian | trixie | fixed | 6.12.85-1 |
| debian | bullseye | fixed | 6.1.170-1~deb11u1 |
| linux-kernel | affected | 5.10.253 | |
| linux-kernel | 7.0 | affected | |
| almalinux | 8 | fixed | kernel-doc-4.18.0-553.126.1.el8_10.noarch.rpm |
Application impact
| Vendor | Product | Versions | Fixed |
|---|---|---|---|
| gcp | | |
References
- https://git.kernel.org/stable/c/2c16e4d64dd91227742dfe196a3e7b0568bef65a
- https://git.kernel.org/stable/c/2cf2737c85a2ba2b52024dafe68ffad2676f97be
- https://git.kernel.org/stable/c/504ba4168466c91210c45acdc332479cfd5f2da6
- https://git.kernel.org/stable/c/5cf28d5c8dcbbe8af6d3b145babe491906d7bad1
- https://git.kernel.org/stable/c/620f3d14c1ef51d425060a3056ad8dbae8f998a3
- https://git.kernel.org/stable/c/90bd7e8501349db3006d21fbc09df9ffcb172965
- https://git.kernel.org/stable/c/a242a9ae58aa46ff7dae51ce64150a93957abe65
- https://git.kernel.org/stable/c/dc1739eff48e34cc71d4e2f03715493fbcebd8af
- https://www.suse.com/security/cve/CVE-2026-43027.html
- https://security-tracker.debian.org/tracker/CVE-2026-43027
- https://access.redhat.com/errata/RHSA-2026:21556
- https://access.redhat.com/errata/RHSA-2026:21706
- https://bugzilla.redhat.com/2404105
- https://bugzilla.redhat.com/2422699
- https://bugzilla.redhat.com/2424879
- https://bugzilla.redhat.com/2429602
- https://bugzilla.redhat.com/2448594
- https://bugzilla.redhat.com/2448745
- https://bugzilla.redhat.com/2454810
- https://bugzilla.redhat.com/2455334
- https://bugzilla.redhat.com/2461107
- https://bugzilla.redhat.com/2461757
- https://bugzilla.redhat.com/2461759
- https://bugzilla.redhat.com/2464369
- https://bugzilla.redhat.com/2464455
CWEs
CWE-416
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.