CVE-2026-31665 (GCVE-0-2026-31665)
Vulnerability from cvelistv5 – Published: 2026-04-24 14:45 – Updated: 2026-04-27 14:04
VLAI?
Title
netfilter: nft_ct: fix use-after-free in timeout object destroy
Summary
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
Severity ?
7.8 (High)
Assigner
References
Impacted products
| Vendor | Product | Version | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux |
Affected:
7e0b2b57f01d183e1c84114f1f2287737358d748 , < c458fc1c278a65ad5381083121d39a479973ebed
(git)
Affected: 7e0b2b57f01d183e1c84114f1f2287737358d748 , < c581e5c8f2b59158f62efe61c1a3dc36189081ff (git) Affected: 7e0b2b57f01d183e1c84114f1f2287737358d748 , < f16fe84879a5280f05ebbcea593a189ba0f3e79a (git) Affected: 7e0b2b57f01d183e1c84114f1f2287737358d748 , < 070abdf1b04325b21a20a2a0c39a2208af107275 (git) Affected: 7e0b2b57f01d183e1c84114f1f2287737358d748 , < aa7cfa16f98f8ec3e6d47c34e1a8c1ae4b9b8b77 (git) Affected: 7e0b2b57f01d183e1c84114f1f2287737358d748 , < b42aca3660dc2627a29a38131597ca610dc451f9 (git) Affected: 7e0b2b57f01d183e1c84114f1f2287737358d748 , < d0983b48c10d1509fd795c155f8b1e832e1369ff (git) Affected: 7e0b2b57f01d183e1c84114f1f2287737358d748 , < f8dca15a1b190787bbd03285304b569631160eda (git) |
|||||||
|
|||||||||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"include/net/netfilter/nf_conntrack_timeout.h",
"net/netfilter/nft_ct.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "c458fc1c278a65ad5381083121d39a479973ebed",
"status": "affected",
"version": "7e0b2b57f01d183e1c84114f1f2287737358d748",
"versionType": "git"
},
{
"lessThan": "c581e5c8f2b59158f62efe61c1a3dc36189081ff",
"status": "affected",
"version": "7e0b2b57f01d183e1c84114f1f2287737358d748",
"versionType": "git"
},
{
"lessThan": "f16fe84879a5280f05ebbcea593a189ba0f3e79a",
"status": "affected",
"version": "7e0b2b57f01d183e1c84114f1f2287737358d748",
"versionType": "git"
},
{
"lessThan": "070abdf1b04325b21a20a2a0c39a2208af107275",
"status": "affected",
"version": "7e0b2b57f01d183e1c84114f1f2287737358d748",
"versionType": "git"
},
{
"lessThan": "aa7cfa16f98f8ec3e6d47c34e1a8c1ae4b9b8b77",
"status": "affected",
"version": "7e0b2b57f01d183e1c84114f1f2287737358d748",
"versionType": "git"
},
{
"lessThan": "b42aca3660dc2627a29a38131597ca610dc451f9",
"status": "affected",
"version": "7e0b2b57f01d183e1c84114f1f2287737358d748",
"versionType": "git"
},
{
"lessThan": "d0983b48c10d1509fd795c155f8b1e832e1369ff",
"status": "affected",
"version": "7e0b2b57f01d183e1c84114f1f2287737358d748",
"versionType": "git"
},
{
"lessThan": "f8dca15a1b190787bbd03285304b569631160eda",
"status": "affected",
"version": "7e0b2b57f01d183e1c84114f1f2287737358d748",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"include/net/netfilter/nf_conntrack_timeout.h",
"net/netfilter/nft_ct.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "4.19"
},
{
"lessThan": "4.19",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.253",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.203",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.169",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.135",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.82",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.23",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.19.*",
"status": "unaffected",
"version": "6.19.13",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.10.253",
"versionStartIncluding": "4.19",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.15.203",
"versionStartIncluding": "4.19",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.169",
"versionStartIncluding": "4.19",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.6.135",
"versionStartIncluding": "4.19",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.82",
"versionStartIncluding": "4.19",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.23",
"versionStartIncluding": "4.19",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.19.13",
"versionStartIncluding": "4.19",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.0",
"versionStartIncluding": "4.19",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_ct: fix use-after-free in timeout object destroy\n\nnft_ct_timeout_obj_destroy() frees the timeout object with kfree()\nimmediately after nf_ct_untimeout(), without waiting for an RCU grace\nperiod. Concurrent packet processing on other CPUs may still hold\nRCU-protected references to the timeout object obtained via\nrcu_dereference() in nf_ct_timeout_data().\n\nAdd an rcu_head to struct nf_ct_timeout and use kfree_rcu() to defer\nfreeing until after an RCU grace period, matching the approach already\nused in nfnetlink_cttimeout.c.\n\nKASAN report:\n BUG: KASAN: slab-use-after-free in nf_conntrack_tcp_packet+0x1381/0x29d0\n Read of size 4 at addr ffff8881035fe19c by task exploit/80\n\n Call Trace:\n nf_conntrack_tcp_packet+0x1381/0x29d0\n nf_conntrack_in+0x612/0x8b0\n nf_hook_slow+0x70/0x100\n __ip_local_out+0x1b2/0x210\n tcp_sendmsg_locked+0x722/0x1580\n __sys_sendto+0x2d8/0x320\n\n Allocated by task 75:\n nft_ct_timeout_obj_init+0xf6/0x290\n nft_obj_init+0x107/0x1b0\n nf_tables_newobj+0x680/0x9c0\n nfnetlink_rcv_batch+0xc29/0xe00\n\n Freed by task 26:\n nft_obj_destroy+0x3f/0xa0\n nf_tables_trans_destroy_work+0x51c/0x5c0\n process_one_work+0x2c4/0x5a0"
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-04-27T14:04:49.358Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/c458fc1c278a65ad5381083121d39a479973ebed"
},
{
"url": "https://git.kernel.org/stable/c/c581e5c8f2b59158f62efe61c1a3dc36189081ff"
},
{
"url": "https://git.kernel.org/stable/c/f16fe84879a5280f05ebbcea593a189ba0f3e79a"
},
{
"url": "https://git.kernel.org/stable/c/070abdf1b04325b21a20a2a0c39a2208af107275"
},
{
"url": "https://git.kernel.org/stable/c/aa7cfa16f98f8ec3e6d47c34e1a8c1ae4b9b8b77"
},
{
"url": "https://git.kernel.org/stable/c/b42aca3660dc2627a29a38131597ca610dc451f9"
},
{
"url": "https://git.kernel.org/stable/c/d0983b48c10d1509fd795c155f8b1e832e1369ff"
},
{
"url": "https://git.kernel.org/stable/c/f8dca15a1b190787bbd03285304b569631160eda"
}
],
"title": "netfilter: nft_ct: fix use-after-free in timeout object destroy",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-31665",
"datePublished": "2026-04-24T14:45:14.613Z",
"dateReserved": "2026-03-09T15:48:24.129Z",
"dateUpdated": "2026-04-27T14:04:49.358Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-31665",
"date": "2026-05-05",
"epss": "0.00013",
"percentile": "0.02396"
},
"nvd": "{\"cve\":{\"id\":\"CVE-2026-31665\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-04-24T15:16:46.157\",\"lastModified\":\"2026-04-27T20:00:05.430\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nnetfilter: nft_ct: fix use-after-free in timeout object destroy\\n\\nnft_ct_timeout_obj_destroy() frees the timeout object with kfree()\\nimmediately after nf_ct_untimeout(), without waiting for an RCU grace\\nperiod. Concurrent packet processing on other CPUs may still hold\\nRCU-protected references to the timeout object obtained via\\nrcu_dereference() in nf_ct_timeout_data().\\n\\nAdd an rcu_head to struct nf_ct_timeout and use kfree_rcu() to defer\\nfreeing until after an RCU grace period, matching the approach already\\nused in nfnetlink_cttimeout.c.\\n\\nKASAN report:\\n BUG: KASAN: slab-use-after-free in nf_conntrack_tcp_packet+0x1381/0x29d0\\n Read of size 4 at addr ffff8881035fe19c by task exploit/80\\n\\n Call Trace:\\n nf_conntrack_tcp_packet+0x1381/0x29d0\\n nf_conntrack_in+0x612/0x8b0\\n nf_hook_slow+0x70/0x100\\n __ip_local_out+0x1b2/0x210\\n tcp_sendmsg_locked+0x722/0x1580\\n __sys_sendto+0x2d8/0x320\\n\\n Allocated by task 75:\\n nft_ct_timeout_obj_init+0xf6/0x290\\n nft_obj_init+0x107/0x1b0\\n nf_tables_newobj+0x680/0x9c0\\n nfnetlink_rcv_batch+0xc29/0xe00\\n\\n Freed by task 26:\\n nft_obj_destroy+0x3f/0xa0\\n nf_tables_trans_destroy_work+0x51c/0x5c0\\n process_one_work+0x2c4/0x5a0\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}]},\"weaknesses\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-416\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"4.19.1\",\"versionEndExcluding\":\"5.10.253\",\"matchCriteriaId\":\"DCA68506-DA89-4BB0-BB51-9DE08D03AA32\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"5.11\",\"versionEndExcluding\":\"5.15.203\",\"matchCriteriaId\":\"20DDB3E9-AABF-4107-ADB0-5362AA067045\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"5.16\",\"versionEndExcluding\":\"6.1.169\",\"matchCriteriaId\":\"DBEC0E5D-641C-4E98-A6D9-5799B10CE451\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.2\",\"versionEndExcluding\":\"6.6.135\",\"matchCriteriaId\":\"15C1A1B2-14EE-494C-AF3E-D5A7BA640B39\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.7\",\"versionEndExcluding\":\"6.12.82\",\"matchCriteriaId\":\"02904CAE-71D2-45B3-9EC3-F6A9D18B6307\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.13\",\"versionEndExcluding\":\"6.18.23\",\"matchCriteriaId\":\"E9E09FDD-9EE3-4A56-92E2-2B30AFD0072F\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.19\",\"versionEndExcluding\":\"6.19.13\",\"matchCriteriaId\":\"1490EF9B-9080-481C-8D22-1306AAE664E4\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:4.19:-:*:*:*:*:*:*\",\"matchCriteriaId\":\"CFDAD450-8799-4C2D-80CE-2AA45DEC35CE\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*\",\"matchCriteriaId\":\"F253B622-8837-4245-BCE5-A7BF8FC76A16\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*\",\"matchCriteriaId\":\"4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*\",\"matchCriteriaId\":\"F666C8D8-6538-46D4-B318-87610DE64C34\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*\",\"matchCriteriaId\":\"02259FDA-961B-47BC-AE7F-93D7EC6E90C2\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*\",\"matchCriteriaId\":\"58A9FEFF-C040-420D-8F0A-BFDAAA1DF258\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*\",\"matchCriteriaId\":\"1D2315C0-D46F-4F85-9754-F9E5E11374A6\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:*\",\"matchCriteriaId\":\"512EE3A8-A590-4501-9A94-5D4B268D6138\"}]}]}],\"references\":[{\"url\":\"https://git.kernel.org/stable/c/070abdf1b04325b21a20a2a0c39a2208af107275\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/aa7cfa16f98f8ec3e6d47c34e1a8c1ae4b9b8b77\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/b42aca3660dc2627a29a38131597ca610dc451f9\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/c458fc1c278a65ad5381083121d39a479973ebed\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/c581e5c8f2b59158f62efe61c1a3dc36189081ff\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/d0983b48c10d1509fd795c155f8b1e832e1369ff\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/f16fe84879a5280f05ebbcea593a189ba0f3e79a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/f8dca15a1b190787bbd03285304b569631160eda\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]}]}}"
}
}
Loading…
Loading…
Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Loading…
Loading…