CVE-2026-23458netfilter: ctnetlink: fix use-after-free in ctnetlink_dump_exp_ct()
Updated under an hour ago ()
Does this affect you?
It affects Linux and 4 other products. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
Do this next
Free account, 1 product
In the Linux kernel, the following vulnerability has been resolved: netfilter: ctnetlink: fix use-after-free in ctnetlink_dump_exp_ct() ctnetlink_dump_exp_ct() stores a conntrack pointer in cb->data for the netlink dump callback ctnetlink_exp_ct_dump_table(), but drops the conntrack reference immediately after netlink_dump_start(). When the dump spans multiple rounds, the second recvmsg() triggers the dump callback which dereferences the now-freed conntrack via nfct_help(ct), leading to a use-after-free on ct->ext. The bug is that the netlink_dump_control has no .start or .done callbacks to manage the conntrack reference across dump rounds. Other dump functions in the same file (e.g. ctnetlink_get_conntrack) properly use .start/.done callbacks for this purpose. Fix this by adding .start and .done callbacks that hold and release the conntrack reference for the duration of the dump, and move the nfct_help() call after the cb->args[0] early-return check in the dump callback to avoid dereferencing ct->ext unnecessarily. BUG: KASAN: slab-use-after-free in ctnetlink_exp_ct_dump_table+0x4f/0x2e0 Read of size 8 at addr ffff88810597ebf0 by task ctnetlink_poc/133 CPU: 1 UID: 0 PID: 133 Comm: ctnetlink_poc Not tainted 7.0.0-rc2+ #3 PREEMPTLAZY Call Trace: <TASK> ctnetlink_exp_ct_dump_table+0x4f/0x2e0 netlink_dump+0x333/0x880 netlink_recvmsg+0x3e2/0x4b0 ? aa_sk_perm+0x184/0x450 sock_recvmsg+0xde/0xf0 Allocated by task 133: kmem_cache_alloc_noprof+0x134/0x440 __nf_conntrack_alloc+0xa8/0x2b0 ctnetlink_create_conntrack+0xa1/0x900 ctnetlink_new_conntrack+0x3cf/0x7d0 nfnetlink_rcv_msg+0x48e/0x510 netlink_rcv_skb+0xc9/0x1f0 nfnetlink_rcv+0xdb/0x220 netlink_unicast+0x3ec/0x590 netlink_sendmsg+0x397/0x690 __sys_sendmsg+0xf4/0x180 Freed by task 0: slab_free_after_rcu_debug+0xad/0x1e0 rcu_core+0x5c3/0x9c0
- CVSS
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Modified
- Record last updated
- Oct 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from e844a928431fa8f1359d1f4f2cef53d9b446bf52 before d8cd0efbccc5cfb0a80da744a7da76e1333ab925; from e844a928431fa8f1359d1f4f2cef53d9b446bf52 before 9821b47f669eb82791fa0b1a6ebaf9aa219bea72; from e844a928431fa8f1359d1f4f2cef53d9b446bf52 before bdf2724eefd4455a66863abb025bab8d3aa98c57; from e844a928431fa8f1359d1f4f2cef53d9b446bf52 before f04cc86d59906513d2d62183b882966fc0ae0390; from e844a928431fa8f1359d1f4f2cef53d9b446bf52 before f025171feef2ac65663d7986f1d5ff0c28d6b2a9; from e844a928431fa8f1359d1f4f2cef53d9b446bf52 before 04c8907ce4e3d3e26c5e1a3e47aa5d17082cbb56; from e844a928431fa8f1359d1f4f2cef53d9b446bf52 before cd541f15b60e2257441398cf495d978f816d09f8; from e844a928431fa8f1359d1f4f2cef53d9b446bf52 before 5cb81eeda909dbb2def209dd10636b51549a3f8a | CNA record |
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.6 | CISA ADP |
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name) | from V3.1.6 | CISA ADP |
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.6 | CISA ADP |
linux linux_kernel linux:linux_kernel | from 3.10 before 5.10.253; from 5.11 before 5.15.203; from 5.16 before 6.1.167; from 6.2 before 6.6.130; from 6.7 before 6.12.78; from 6.13 before 6.18.20; from 6.19 before 6.19.10; 7.0; and 3 more ranges | NVD |
References
- https://git.kernel.org/stable/c/d8cd0efbccc5cfb0a80da744a7da76e1333ab925patch
- https://git.kernel.org/stable/c/9821b47f669eb82791fa0b1a6ebaf9aa219bea72patch
- https://git.kernel.org/stable/c/bdf2724eefd4455a66863abb025bab8d3aa98c57patch
- https://git.kernel.org/stable/c/f04cc86d59906513d2d62183b882966fc0ae0390patch
- https://git.kernel.org/stable/c/f025171feef2ac65663d7986f1d5ff0c28d6b2a9patch
- https://git.kernel.org/stable/c/04c8907ce4e3d3e26c5e1a3e47aa5d17082cbb56patch
- https://git.kernel.org/stable/c/cd541f15b60e2257441398cf495d978f816d09f8patch
- https://git.kernel.org/stable/c/5cb81eeda909dbb2def209dd10636b51549a3f8apatch
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- https://cert-portal.siemens.com/productcert/html/ssa-082556.html
- https://cert-portal.siemens.com/productcert/html/ssa-457936.html
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.