FKIE_CVE-2026-74660
Vulnerability from fkie_nvd - Published: 2026-08-22 16:16 - Updated: 2026-08-25 06:18
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
netfilter: ebt_nflog: pin the NFLOG backend
nf_log_unregister() runs after the per-net teardown so its final RCU
grace period also drains readers that obtained the logger from a per-net
binding. However, ebt_nflog passes an explicit ULOG log type to
nf_log_packet() without holding a reference on the selected logger module,
unlike the xt_NFLOG and nft_log frontends.
An ebtables nflog rule can therefore remain callable while nfnetlink_log
is unloaded. The resulting interleaving is:
CPU 0 CPU 1
nfnetlink_log_fini()
unregister_pernet_subsys()
kfree(nfnl_log_pernet(net))
ebt_nflog_tg()
nf_log_packet()
nfulnl_log_packet()
instance_lookup_get_rcu()
The global ULOG logger is still registered at this point, so CPU 1
dereferences the per-net state after CPU 0 has freed it. KASAN reported:
BUG: KASAN: slab-use-after-free in instance_lookup_get_rcu
Read of size 8 at addr ff110001052e6210 by task poc/92
Call Trace:
instance_lookup_get_rcu+0x1ce/0x1f0 [nfnetlink_log]
nfulnl_log_packet+0x248/0x2fb0 [nfnetlink_log]
nf_log_packet+0x204/0x300
ebt_nflog_tg+0x351/0x550
ebt_do_table+0xedf/0x22b0
Allocated by task 90:
__kmalloc_noprof+0x186/0x470
ops_init+0x6d/0x420
register_pernet_operations+0x2f6/0x670
register_pernet_subsys+0x23/0x40
Freed by task 93:
kfree+0x131/0x3c0
ops_undo_list+0x3e3/0x700
unregister_pernet_operations+0x232/0x490
unregister_pernet_subsys+0x1c/0x30
nfnetlink_log_fini+0x34/0x450 [nfnetlink_log]
Acquire the ULOG logger module reference when an ebt_nflog rule is
validated and release it when the rule is destroyed. Request the NFLOG
backend for legacy callers when needed, matching xt_NFLOG. This prevents
module teardown until all ebt_nflog rules have stopped using the logger.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/bridge/netfilter/ebt_nflog.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "3bcce49d617c593c7606083bfdb464a1761fa68d",
"status": "affected",
"version": "c83fa19603bdaeef17b815713dbbe3230c8a34ee",
"versionType": "git"
},
{
"lessThan": "394d7939c6b2b9e6bea0844c89efb5913168d898",
"status": "affected",
"version": "c83fa19603bdaeef17b815713dbbe3230c8a34ee",
"versionType": "git"
},
{
"lessThan": "2cac4294f184c9bc19ff82552c62b80498694c39",
"status": "affected",
"version": "c83fa19603bdaeef17b815713dbbe3230c8a34ee",
"versionType": "git"
},
{
"lessThan": "9d8a94b48b393885e7f876c8ef68ed4da5012078",
"status": "affected",
"version": "c83fa19603bdaeef17b815713dbbe3230c8a34ee",
"versionType": "git"
},
{
"lessThan": "6809379a860b9fccbb5435bf08343f6d081ac68d",
"status": "affected",
"version": "c83fa19603bdaeef17b815713dbbe3230c8a34ee",
"versionType": "git"
},
{
"lessThan": "47a119ec8a7e2d5c8c4e86fb1a56c4e696e500fb",
"status": "affected",
"version": "c83fa19603bdaeef17b815713dbbe3230c8a34ee",
"versionType": "git"
},
{
"lessThan": "e2ab7e878bdbe80104c879c31fd2d82a476703b8",
"status": "affected",
"version": "c83fa19603bdaeef17b815713dbbe3230c8a34ee",
"versionType": "git"
},
{
"lessThan": "30825970339c107bacaf7f61af90fcdb1f597ca1",
"status": "affected",
"version": "c83fa19603bdaeef17b815713dbbe3230c8a34ee",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/bridge/netfilter/ebt_nflog.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "4.12"
},
{
"lessThan": "4.12",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.265",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.216",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.183",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.152",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.104",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.45",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.9",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ebt_nflog: pin the NFLOG backend\n\nnf_log_unregister() runs after the per-net teardown so its final RCU\ngrace period also drains readers that obtained the logger from a per-net\nbinding. However, ebt_nflog passes an explicit ULOG log type to\nnf_log_packet() without holding a reference on the selected logger module,\nunlike the xt_NFLOG and nft_log frontends.\n\nAn ebtables nflog rule can therefore remain callable while nfnetlink_log\nis unloaded. The resulting interleaving is:\n\n CPU 0 CPU 1\n nfnetlink_log_fini()\n unregister_pernet_subsys()\n kfree(nfnl_log_pernet(net))\n ebt_nflog_tg()\n nf_log_packet()\n nfulnl_log_packet()\n instance_lookup_get_rcu()\n\nThe global ULOG logger is still registered at this point, so CPU 1\ndereferences the per-net state after CPU 0 has freed it. KASAN reported:\n\n BUG: KASAN: slab-use-after-free in instance_lookup_get_rcu\n Read of size 8 at addr ff110001052e6210 by task poc/92\n Call Trace:\n instance_lookup_get_rcu+0x1ce/0x1f0 [nfnetlink_log]\n nfulnl_log_packet+0x248/0x2fb0 [nfnetlink_log]\n nf_log_packet+0x204/0x300\n ebt_nflog_tg+0x351/0x550\n ebt_do_table+0xedf/0x22b0\n Allocated by task 90:\n __kmalloc_noprof+0x186/0x470\n ops_init+0x6d/0x420\n register_pernet_operations+0x2f6/0x670\n register_pernet_subsys+0x23/0x40\n Freed by task 93:\n kfree+0x131/0x3c0\n ops_undo_list+0x3e3/0x700\n unregister_pernet_operations+0x232/0x490\n unregister_pernet_subsys+0x1c/0x30\n nfnetlink_log_fini+0x34/0x450 [nfnetlink_log]\n\nAcquire the ULOG logger module reference when an ebt_nflog rule is\nvalidated and release it when the rule is destroyed. Request the NFLOG\nbackend for legacy callers when needed, matching xt_NFLOG. This prevents\nmodule teardown until all ebt_nflog rules have stopped using the logger."
}
],
"id": "CVE-2026-74660",
"lastModified": "2026-08-25T06:18:46.943",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-08-22T16:16:39.743",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/2cac4294f184c9bc19ff82552c62b80498694c39"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/30825970339c107bacaf7f61af90fcdb1f597ca1"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/394d7939c6b2b9e6bea0844c89efb5913168d898"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/3bcce49d617c593c7606083bfdb464a1761fa68d"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/47a119ec8a7e2d5c8c4e86fb1a56c4e696e500fb"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/6809379a860b9fccbb5435bf08343f6d081ac68d"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/9d8a94b48b393885e7f876c8ef68ed4da5012078"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/e2ab7e878bdbe80104c879c31fd2d82a476703b8"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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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.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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