netfilter: nft_ct: fix use-after-free in timeout object destroy
In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_ct: fix use-after-free in timeout object destroy nft_ct_timeout_obj_destroy() frees the timeout object with kfree() immediately after nf_ct_untimeout(), without waiting for an RCU grace period. Concurrent packet processing on other CPUs may still hold RCU-protected references to the timeout object obtained via rcu_dereference() in nf_ct_timeout_data(). Add an rcu_head to struct nf_ct_timeout and use kfree_rcu() to defer freeing until after an RCU grace period, matching the approach already used in nfnetlink_cttimeout.c. KASAN report: BUG: KASAN: slab-use-after-free in nf_conntrack_tcp_packet+0x1381/0x29d0 Read of size 4 at addr ffff8881035fe19c by task exploit/80 Call Trace: nf_conntrack_tcp_packet+0x1381/0x29d0 nf_conntrack_in+0x612/0x8b0 nf_hook_slow+0x70/0x100 __ip_local_out+0x1b2/0x210 tcp_sendmsg_locked+0x722/0x1580 __sys_sendto+0x2d8/0x320 Allocated by task 75: nft_ct_timeout_obj_init+0xf6/0x290 nft_obj_init+0x107/0x1b0 nf_tables_newobj+0x680/0x9c0 nfnetlink_rcv_batch+0xc29/0xe00 Freed by task 26: nft_obj_destroy+0x3f/0xa0 nf_tables_trans_destroy_work+0x51c/0x5c0 process_one_work+0x2c4/0x5a0
CVE-2026-31665
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-2026-31665
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": "7e0b2b57f01d183e1c84114f1f2287737358d748",
"lessThan": "c458fc1c278a65ad5381083121d39a479973ebed",
"versionType": "git"
},
{
"status": "affected",
"version": "7e0b2b57f01d183e1c84114f1f2287737358d748",
"lessThan": "c581e5c8f2b59158f62efe61c1a3dc36189081ff",
"versionType": "git"
},
{
"status": "affected",
"version": "7e0b2b57f01d183e1c84114f1f2287737358d748",
"lessThan": "f16fe84879a5280f05ebbcea593a189ba0f3e79a",
"versionType": "git"
},
{
"status": "affected",
"version": "7e0b2b57f01d183e1c84114f1f2287737358d748",
"lessThan": "070abdf1b04325b21a20a2a0c39a2208af107275",
"versionType": "git"
},
{
"status": "affected",
"version": "7e0b2b57f01d183e1c84114f1f2287737358d748",
"lessThan": "aa7cfa16f98f8ec3e6d47c34e1a8c1ae4b9b8b77",
"versionType": "git"
},
{
"status": "affected",
"version": "7e0b2b57f01d183e1c84114f1f2287737358d748",
"lessThan": "b42aca3660dc2627a29a38131597ca610dc451f9",
"versionType": "git"
},
{
"status": "affected",
"version": "7e0b2b57f01d183e1c84114f1f2287737358d748",
"lessThan": "d0983b48c10d1509fd795c155f8b1e832e1369ff",
"versionType": "git"
},
{
"status": "affected",
"version": "7e0b2b57f01d183e1c84114f1f2287737358d748",
"lessThan": "f8dca15a1b190787bbd03285304b569631160eda",
"versionType": "git"
}
],
"programFiles": [
"include/net/netfilter/nf_conntrack_timeout.h",
"net/netfilter/nft_ct.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.19"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.19",
"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": "6.1.169",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.135",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.82",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.23",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "6.19.13",
"versionType": "semver",
"lessThanOrEqual": "6.19.*"
},
{
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"include/net/netfilter/nf_conntrack_timeout.h",
"net/netfilter/nft_ct.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-31665
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #39941 · Revision 1
- Added to Heist Feed
- Publisher date