netfilter: nft_ct: fix use-after-free in timeout object destroy
Summary
| CVE | CVE-2026-31665 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-04-24 15:16:46 UTC |
| Updated | 2026-04-24 17:51:40 UTC |
| Description | 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 |
Risk And Classification
EPSS: 0.000240000 probability, percentile 0.068020000 (date 2026-04-25)
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected 7e0b2b57f01d183e1c84114f1f2287737358d748 c458fc1c278a65ad5381083121d39a479973ebed git | Not specified |
| CNA | Linux | Linux | affected 7e0b2b57f01d183e1c84114f1f2287737358d748 c581e5c8f2b59158f62efe61c1a3dc36189081ff git | Not specified |
| CNA | Linux | Linux | affected 7e0b2b57f01d183e1c84114f1f2287737358d748 f16fe84879a5280f05ebbcea593a189ba0f3e79a git | Not specified |
| CNA | Linux | Linux | affected 7e0b2b57f01d183e1c84114f1f2287737358d748 070abdf1b04325b21a20a2a0c39a2208af107275 git | Not specified |
| CNA | Linux | Linux | affected 7e0b2b57f01d183e1c84114f1f2287737358d748 aa7cfa16f98f8ec3e6d47c34e1a8c1ae4b9b8b77 git | Not specified |
| CNA | Linux | Linux | affected 7e0b2b57f01d183e1c84114f1f2287737358d748 b42aca3660dc2627a29a38131597ca610dc451f9 git | Not specified |
| CNA | Linux | Linux | affected 7e0b2b57f01d183e1c84114f1f2287737358d748 d0983b48c10d1509fd795c155f8b1e832e1369ff git | Not specified |
| CNA | Linux | Linux | affected 7e0b2b57f01d183e1c84114f1f2287737358d748 f8dca15a1b190787bbd03285304b569631160eda git | Not specified |
| CNA | Linux | Linux | affected 4.19 | Not specified |
| CNA | Linux | Linux | unaffected 4.19 semver | Not specified |
| CNA | Linux | Linux | unaffected 5.10.253 5.10.* semver | Not specified |
| CNA | Linux | Linux | unaffected 5.15.203 5.15.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.1.169 6.1.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.6.135 6.6.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.12.82 6.12.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.18.23 6.18.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.19.13 6.19.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.0 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/c458fc1c278a65ad5381083121d39a479973ebed | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/aa7cfa16f98f8ec3e6d47c34e1a8c1ae4b9b8b77 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/d0983b48c10d1509fd795c155f8b1e832e1369ff | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/b42aca3660dc2627a29a38131597ca610dc451f9 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/070abdf1b04325b21a20a2a0c39a2208af107275 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/f8dca15a1b190787bbd03285304b569631160eda | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/f16fe84879a5280f05ebbcea593a189ba0f3e79a | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/c581e5c8f2b59158f62efe61c1a3dc36189081ff | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.