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TI-2026-31207 Aliases CVE-2026-43027GHSA-f42g-qv35-qm2v

netfilter: nf_conntrack_helper: pass helper to expect cleanup

Priority LOW 33CWE-416Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 38 fixed, 2 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-416 and the CVSS impact.

Summary

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)

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00131 2nd percentileScored 2026-11-07
Fix Partial Linux (Linux): 5.10.253, 5.15.203, 6.1.168 +5Red Hat: 12 advisoriesRed Hat: 38 fixed, 2 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux4.14 and later5.10.253, 5.15.203, 6.1.168, 6.6.134, 6.12.81, 6.18.22, 6.19.12, 7.0Patch availableCNA
  • Linux VendorLinux Affected 4.14 and later Fixed in 5.10.253, 5.15.203, 6.1.168, 6.6.134, 6.12.81, 6.18.22, 6.19.12, 7.0 Patch available CNA

CPE configurations NVD · 7

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*4.14 to before 5.10.253; 5.11 to before 5.15.203; 5.16 to before 6.1.168; 6.2 to before 6.6.134; 6.7 to before 6.12.81; 6.13 to before 6.18.22; 6.19 to before 6.19.12VulnerableLinux
cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*7.0 rc1VulnerableLinux
cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*7.0 rc2VulnerableLinux
cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*7.0 rc3VulnerableLinux
cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*7.0 rc4VulnerableLinux
cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*7.0 rc5VulnerableLinux
cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*7.0 rc6VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 4.14 to before 5.10.253; 5.11 to before 5.15.203; 5.16 to before 6.1.168; 6.2 to before 6.6.134; 6.7 to before 6.12.81; 6.13 to before 6.18.22; 6.19 to before 6.19.12 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* Versions 7.0 rc1 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* Versions 7.0 rc2 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:* Versions 7.0 rc3 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:* Versions 7.0 rc4 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:* Versions 7.0 rc5 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:* Versions 7.0 rc6 Vulnerable ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 5.10.253, 5.15.203, 6.1.168, 6.6.134, 6.12.81, 6.18.22, 6.19.12, 7.0

Red Hat 12 advisories

  • RHSA-2026:47633 Released 2026-07-30 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux BaseOS AUS (v.8.4) bpftool-4.18.0-305.199.1.el8_4, kernel-4.18.0-305.199.1.el8_4, kernel-abi-stablelists-4.18.0-305.199.1.el8_4 +14
    • Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4) bpftool-4.18.0-305.199.1.el8_4, kernel-4.18.0-305.199.1.el8_4, kernel-abi-stablelists-4.18.0-305.199.1.el8_4 +14
  • RHSA-2026:40760 Released 2026-07-16 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux BaseOS E4S (v.8.8) bpftool-4.18.0-477.152.1.el8_8, kernel-4.18.0-477.152.1.el8_8, kernel-abi-stablelists-4.18.0-477.152.1.el8_8 +14
    • Red Hat Enterprise Linux BaseOS TUS (v.8.8) bpftool-4.18.0-477.152.1.el8_8, kernel-4.18.0-477.152.1.el8_8, kernel-abi-stablelists-4.18.0-477.152.1.el8_8 +14
  • RHSA-2026:40082 Released 2026-07-15 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux AppStream E4S (v.9.2) kernel-64k-debug-devel-5.14.0-284.181.1.el9_2, kernel-64k-debug-devel-matched-5.14.0-284.181.1.el9_2, kernel-64k-devel-5.14.0-284.181.1.el9_2 +10
    • Red Hat Enterprise Linux BaseOS E4S (v.9.2) bpftool-7.0.0-284.181.1.el9_2, kernel-5.14.0-284.181.1.el9_2, kernel-64k-5.14.0-284.181.1.el9_2 +29
Show 9 more Red Hat advisories
  • RHSA-2026:40068 Released 2026-07-15 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux BaseOS AUS (v.8.6) bpftool-4.18.0-372.201.1.el8_6, kernel-4.18.0-372.201.1.el8_6, kernel-abi-stablelists-4.18.0-372.201.1.el8_6 +14
    • Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6) bpftool-4.18.0-372.201.1.el8_6, kernel-4.18.0-372.201.1.el8_6, kernel-abi-stablelists-4.18.0-372.201.1.el8_6 +14
  • RHSA-2026:39983 Released 2026-07-15 · Red Hat rating Moderate
    kernel-rt security update
    • Red Hat Enterprise Linux Real Time E4S (v.9.2) kernel-rt-5.14.0-284.181.1.rt14.466.el9_2, kernel-rt-core-5.14.0-284.181.1.rt14.466.el9_2, kernel-rt-debug-5.14.0-284.181.1.rt14.466.el9_2 +9
    • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2) kernel-rt-5.14.0-284.181.1.rt14.466.el9_2, kernel-rt-core-5.14.0-284.181.1.rt14.466.el9_2, kernel-rt-debug-5.14.0-284.181.1.rt14.466.el9_2 +11
  • RHSA-2026:39371 Released 2026-07-14 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux AppStream EUS (v. 10.0) kernel-64k-debug-devel-6.12.0-55.88.1.el10_0, kernel-64k-debug-devel-matched-6.12.0-55.88.1.el10_0, kernel-64k-devel-6.12.0-55.88.1.el10_0 +12
    • Red Hat Enterprise Linux BaseOS EUS (v. 10.0) kernel-6.12.0-55.88.1.el10_0, kernel-64k-6.12.0-55.88.1.el10_0, kernel-64k-core-6.12.0-55.88.1.el10_0 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) kernel-tools-libs-devel-6.12.0-55.88.1.el10_0, libperf-6.12.0-55.88.1.el10_0
    • Red Hat Enterprise Linux Real Time EUS (v. 10.0) kernel-rt-6.12.0-55.88.1.el10_0, kernel-rt-64k-6.12.0-55.88.1.el10_0, kernel-rt-64k-core-6.12.0-55.88.1.el10_0 +21
    • Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0) kernel-rt-6.12.0-55.88.1.el10_0, kernel-rt-core-6.12.0-55.88.1.el10_0, kernel-rt-debug-6.12.0-55.88.1.el10_0 +11
  • RHSA-2026:36767 Released 2026-07-08 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream E4S (v.9.4) kernel-64k-debug-devel-5.14.0-427.136.1.el9_4, kernel-64k-debug-devel-matched-5.14.0-427.136.1.el9_4, kernel-64k-devel-5.14.0-427.136.1.el9_4 +11
    • Red Hat Enterprise Linux BaseOS E4S (v.9.4) bpftool-7.3.0-427.136.1.el9_4, kernel-5.14.0-427.136.1.el9_4, kernel-64k-5.14.0-427.136.1.el9_4 +29
    • Red Hat Enterprise Linux Real Time E4S (v.9.4) kernel-rt-5.14.0-427.136.1.el9_4, kernel-rt-core-5.14.0-427.136.1.el9_4, kernel-rt-debug-5.14.0-427.136.1.el9_4 +9
    • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4) kernel-rt-5.14.0-427.136.1.el9_4, kernel-rt-core-5.14.0-427.136.1.el9_4, kernel-rt-debug-5.14.0-427.136.1.el9_4 +11
  • RHSA-2026:34094 Released 2026-07-01 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat CodeReady Linux Builder EUS (v.9.6) kernel-tools-libs-devel-5.14.0-570.125.1.el9_6, libperf-5.14.0-570.125.1.el9_6
    • Red Hat Enterprise Linux AppStream EUS (v.9.6) kernel-64k-debug-devel-5.14.0-570.125.1.el9_6, kernel-64k-debug-devel-matched-5.14.0-570.125.1.el9_6, kernel-64k-devel-5.14.0-570.125.1.el9_6 +12
    • Red Hat Enterprise Linux BaseOS EUS (v.9.6) kernel-5.14.0-570.125.1.el9_6, kernel-64k-5.14.0-570.125.1.el9_6, kernel-64k-core-5.14.0-570.125.1.el9_6 +28
    • Red Hat Enterprise Linux Real Time EUS (v.9.6) kernel-rt-5.14.0-570.125.1.el9_6, kernel-rt-64k-5.14.0-570.125.1.el9_6, kernel-rt-64k-core-5.14.0-570.125.1.el9_6 +21
    • Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) kernel-rt-5.14.0-570.125.1.el9_6, kernel-rt-core-5.14.0-570.125.1.el9_6, kernel-rt-debug-5.14.0-570.125.1.el9_6 +11
  • RHSA-2026:21745 Released 2026-05-28 · Red Hat rating Important
    kernel-rt security update
    • Red Hat Enterprise Linux NFV (v. 8) kernel-rt-4.18.0-553.126.1.rt7.467.el8_10, kernel-rt-core-4.18.0-553.126.1.rt7.467.el8_10, kernel-rt-debug-4.18.0-553.126.1.rt7.467.el8_10 +9
    • Red Hat Enterprise Linux RT (v. 8) kernel-rt-4.18.0-553.126.1.rt7.467.el8_10, kernel-rt-core-4.18.0-553.126.1.rt7.467.el8_10, kernel-rt-debug-4.18.0-553.126.1.rt7.467.el8_10 +7
  • RHSA-2026:21706 Released 2026-05-28 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-553.126.1.el8_10, kernel-4.18.0-553.126.1.el8_10, kernel-abi-stablelists-4.18.0-553.126.1.el8_10 +19
    • Red Hat Enterprise Linux CRB (v. 8) kernel-tools-libs-devel-4.18.0-553.126.1.el8_10
  • RHSA-2026:21556 Released 2026-05-28 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-687.12.1.el9_8, kernel-64k-debug-devel-matched-5.14.0-687.12.1.el9_8, kernel-64k-devel-5.14.0-687.12.1.el9_8 +12
    • Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-687.12.1.el9_8, kernel-64k-5.14.0-687.12.1.el9_8, kernel-64k-core-5.14.0-687.12.1.el9_8 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-687.12.1.el9_8, libperf-5.14.0-687.12.1.el9_8
    • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-687.12.1.el9_8, kernel-rt-64k-5.14.0-687.12.1.el9_8, kernel-rt-64k-core-5.14.0-687.12.1.el9_8 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-687.12.1.el9_8, kernel-rt-core-5.14.0-687.12.1.el9_8, kernel-rt-debug-5.14.0-687.12.1.el9_8 +9
  • RHSA-2026:21557 Released 2026-05-28 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-211.18.1.el10_2, kernel-64k-debug-devel-matched-6.12.0-211.18.1.el10_2, kernel-64k-devel-6.12.0-211.18.1.el10_2 +12
    • Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-211.18.1.el10_2, kernel-64k-6.12.0-211.18.1.el10_2, kernel-64k-core-6.12.0-211.18.1.el10_2 +29
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-211.18.1.el10_2, libperf-6.12.0-211.18.1.el10_2
    • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-211.18.1.el10_2, kernel-rt-64k-6.12.0-211.18.1.el10_2, kernel-rt-64k-core-6.12.0-211.18.1.el10_2 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-211.18.1.el10_2, kernel-rt-core-6.12.0-211.18.1.el10_2, kernel-rt-debug-6.12.0-211.18.1.el10_2 +9

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 9AffectedNo fix yet
Red Hat CodeReady Linux Builder EUS (v.9.6)Fixed RHSA-2026:34094
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:21557
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:21556
Red Hat Enterprise Linux AppStream E4S (v.9.2)Fixed RHSA-2026:40082
Red Hat Enterprise Linux AppStream E4S (v.9.4)Fixed RHSA-2026:36767
Red Hat Enterprise Linux AppStream EUS (v. 10.0)Fixed RHSA-2026:39371
Red Hat Enterprise Linux AppStream EUS (v.9.6)Fixed RHSA-2026:34094
Red Hat Enterprise Linux BaseOS (v. 10)Fixed RHSA-2026:21557
Red Hat Enterprise Linux BaseOS (v. 8)Fixed RHSA-2026:21706
Red Hat Enterprise Linux BaseOS (v. 9)Fixed RHSA-2026:21556
Red Hat Enterprise Linux BaseOS AUS (v.8.4)Fixed RHSA-2026:47633
Red Hat Enterprise Linux BaseOS AUS (v.8.6)Fixed RHSA-2026:40068
Red Hat Enterprise Linux BaseOS E4S (v.8.8)Fixed RHSA-2026:40760
Red Hat Enterprise Linux BaseOS E4S (v.9.2)Fixed RHSA-2026:40082
Red Hat Enterprise Linux BaseOS E4S (v.9.4)Fixed RHSA-2026:36767
Red Hat Enterprise Linux BaseOS EUS (v. 10.0)Fixed RHSA-2026:39371
Red Hat Enterprise Linux BaseOS EUS (v.9.6)Fixed RHSA-2026:34094
Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4)Fixed RHSA-2026:47633
Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6)Fixed RHSA-2026:40068
Red Hat Enterprise Linux BaseOS TUS (v.8.8)Fixed RHSA-2026:40760
Red Hat Enterprise Linux CRB (v. 8)Fixed RHSA-2026:21706
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:21557
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2026:21556
Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0)Fixed RHSA-2026:39371
Red Hat Enterprise Linux NFV (v. 8)Fixed RHSA-2026:21745
Red Hat Enterprise Linux RT (v. 8)Fixed RHSA-2026:21745
Red Hat Enterprise Linux Real Time (v. 10)Fixed RHSA-2026:21557
Red Hat Enterprise Linux Real Time (v. 9)Fixed RHSA-2026:21556
Red Hat Enterprise Linux Real Time E4S (v.9.2)Fixed RHSA-2026:39983
Red Hat Enterprise Linux Real Time E4S (v.9.4)Fixed RHSA-2026:36767
Red Hat Enterprise Linux Real Time EUS (v. 10.0)Fixed RHSA-2026:39371
Red Hat Enterprise Linux Real Time EUS (v.9.6)Fixed RHSA-2026:34094
Red Hat Enterprise Linux Real Time for NFV (v. 10)Fixed RHSA-2026:21557
Red Hat Enterprise Linux Real Time for NFV (v. 9)Fixed RHSA-2026:21556
Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2)Fixed RHSA-2026:39983
Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4)Fixed RHSA-2026:36767
Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0)Fixed RHSA-2026:39371
Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6)Fixed RHSA-2026:34094
Not affected: 1 product
  • Red Hat Enterprise Linux 7

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-43027
  2. 2026-10-03 Alias added: GHSA-f42g-qv35-qm2v
  3. 2026-11-06 CISA SSVC decision points changed

References

Patch 8

  • TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
  • TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
  • TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
  • TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
  • TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
See all 15278 →

Sources

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