netfilter: ctnetlink: fix use-after-free in ctnetlink_dump_exp_ct()
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: 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 ctne
CVE-2026-23458
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-23458
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "e844a928431fa8f1359d1f4f2cef53d9b446bf52",
"lessThan": "d8cd0efbccc5cfb0a80da744a7da76e1333ab925",
"versionType": "git"
},
{
"status": "affected",
"version": "e844a928431fa8f1359d1f4f2cef53d9b446bf52",
"lessThan": "9821b47f669eb82791fa0b1a6ebaf9aa219bea72",
"versionType": "git"
},
{
"status": "affected",
"version": "e844a928431fa8f1359d1f4f2cef53d9b446bf52",
"lessThan": "bdf2724eefd4455a66863abb025bab8d3aa98c57",
"versionType": "git"
},
{
"status": "affected",
"version": "e844a928431fa8f1359d1f4f2cef53d9b446bf52",
"lessThan": "f04cc86d59906513d2d62183b882966fc0ae0390",
"versionType": "git"
},
{
"status": "affected",
"version": "e844a928431fa8f1359d1f4f2cef53d9b446bf52",
"lessThan": "f025171feef2ac65663d7986f1d5ff0c28d6b2a9",
"versionType": "git"
},
{
"status": "affected",
"version": "e844a928431fa8f1359d1f4f2cef53d9b446bf52",
"lessThan": "04c8907ce4e3d3e26c5e1a3e47aa5d17082cbb56",
"versionType": "git"
},
{
"status": "affected",
"version": "e844a928431fa8f1359d1f4f2cef53d9b446bf52",
"lessThan": "cd541f15b60e2257441398cf495d978f816d09f8",
"versionType": "git"
},
{
"status": "affected",
"version": "e844a928431fa8f1359d1f4f2cef53d9b446bf52",
"lessThan": "5cb81eeda909dbb2def209dd10636b51549a3f8a",
"versionType": "git"
}
],
"programFiles": [
"net/netfilter/nf_conntrack_netlink.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "3.10"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "3.10",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.253",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.203",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.167",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.130",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.78",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.20",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "6.19.10",
"versionType": "semver",
"lessThanOrEqual": "6.19.*"
},
{
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/netfilter/nf_conntrack_netlink.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-23458
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #39859 · Revision 1
- Added to Heist Feed
- Publisher date