FKIE_CVE-2026-74748
Vulnerability from fkie_nvd - Published: 2026-08-26 15:16 - Updated: 2026-08-27 06:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
netfilter: ipset: fix refcount race between list:set GC and swap
__ip_set_put_byindex() resolved the index to a set pointer under RCU,
then took ip_set_ref_lock in __ip_set_put() to decrement set->ref.
ip_set_swap() holds that same lock while swapping both the ip_set_list
slots and the two sets' ref counters, so it can interleave between the
dereference and the lock acquisition, leaving the caller to decrement a
set whose reference already moved to the other index and hit
BUG_ON(set->ref == 0). list_set_gc() reaches this from timer softirq,
which the nfnl mutex does not serialize against swap: an expiring
list:set member calls list_set_del() -> ip_set_put_byindex() while
IPSET_CMD_SWAP runs on the referenced sets.
Resolve the index and decrement under ip_set_ref_lock, as ip_set_swap()
already does, keeping the refcount tied to the index rather than to a
stale set pointer.
kernel BUG at net/netfilter/ipset/ip_set_core.c:685!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
RIP: 0010:ip_set_put_byindex (net/netfilter/ipset/ip_set_core.c:870)
Call Trace:
<IRQ>
list_set_del (net/netfilter/ipset/ip_set_list_set.c:159)
set_cleanup_entries (net/netfilter/ipset/ip_set_list_set.c:181)
list_set_gc (net/netfilter/ipset/ip_set_list_set.c:578)
call_timer_fn (kernel/time/timer.c:1748)
__run_timers (kernel/time/timer.c:1799 kernel/time/timer.c:2374)
run_timer_softirq (kernel/time/timer.c:2405)
</IRQ>
Kernel panic - not syncing: Fatal exception in interrupt
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/netfilter/ipset/ip_set_core.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "97a01de0c6321b7210d30d0a4d60f10f561097c7",
"status": "affected",
"version": "9076aea76538556224e7d73ab718f8841330818a",
"versionType": "git"
},
{
"lessThan": "c21afc7c216a4d257a4f3f300e0791890bc846b9",
"status": "affected",
"version": "9076aea76538556224e7d73ab718f8841330818a",
"versionType": "git"
},
{
"lessThan": "b0aab9dd1a348b99d75ff52765719d0cc2050630",
"status": "affected",
"version": "9076aea76538556224e7d73ab718f8841330818a",
"versionType": "git"
},
{
"lessThan": "b891e7a6bb06e0f6560e5932665ac660acd12225",
"status": "affected",
"version": "9076aea76538556224e7d73ab718f8841330818a",
"versionType": "git"
},
{
"lessThan": "20cb13a523f0a05cb2d0a7d72abae687683712e0",
"status": "affected",
"version": "9076aea76538556224e7d73ab718f8841330818a",
"versionType": "git"
},
{
"lessThan": "cb20da33839f28f590c99f16bafaa6151451c0e8",
"status": "affected",
"version": "9076aea76538556224e7d73ab718f8841330818a",
"versionType": "git"
},
{
"lessThan": "24ffcb1e1688c55fd2a505f064295cd28eac546d",
"status": "affected",
"version": "9076aea76538556224e7d73ab718f8841330818a",
"versionType": "git"
},
{
"lessThan": "0c88868271653537ed443272dd8e7d13634d214b",
"status": "affected",
"version": "9076aea76538556224e7d73ab718f8841330818a",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/netfilter/ipset/ip_set_core.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "3.8"
},
{
"lessThan": "3.8",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.266",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.217",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.184",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.153",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.105",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.46",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.10",
"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: ipset: fix refcount race between list:set GC and swap\n\n__ip_set_put_byindex() resolved the index to a set pointer under RCU,\nthen took ip_set_ref_lock in __ip_set_put() to decrement set-\u003eref.\nip_set_swap() holds that same lock while swapping both the ip_set_list\nslots and the two sets\u0027 ref counters, so it can interleave between the\ndereference and the lock acquisition, leaving the caller to decrement a\nset whose reference already moved to the other index and hit\nBUG_ON(set-\u003eref == 0). list_set_gc() reaches this from timer softirq,\nwhich the nfnl mutex does not serialize against swap: an expiring\nlist:set member calls list_set_del() -\u003e ip_set_put_byindex() while\nIPSET_CMD_SWAP runs on the referenced sets.\n\nResolve the index and decrement under ip_set_ref_lock, as ip_set_swap()\nalready does, keeping the refcount tied to the index rather than to a\nstale set pointer.\n\n kernel BUG at net/netfilter/ipset/ip_set_core.c:685!\n Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI\n RIP: 0010:ip_set_put_byindex (net/netfilter/ipset/ip_set_core.c:870)\n Call Trace:\n \u003cIRQ\u003e\n list_set_del (net/netfilter/ipset/ip_set_list_set.c:159)\n set_cleanup_entries (net/netfilter/ipset/ip_set_list_set.c:181)\n list_set_gc (net/netfilter/ipset/ip_set_list_set.c:578)\n call_timer_fn (kernel/time/timer.c:1748)\n __run_timers (kernel/time/timer.c:1799 kernel/time/timer.c:2374)\n run_timer_softirq (kernel/time/timer.c:2405)\n \u003c/IRQ\u003e\n Kernel panic - not syncing: Fatal exception in interrupt"
}
],
"id": "CVE-2026-74748",
"lastModified": "2026-08-27T06:17:25.680",
"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": "2026-08-26T15:16:53.770",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/0c88868271653537ed443272dd8e7d13634d214b"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/20cb13a523f0a05cb2d0a7d72abae687683712e0"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/24ffcb1e1688c55fd2a505f064295cd28eac546d"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/97a01de0c6321b7210d30d0a4d60f10f561097c7"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/b0aab9dd1a348b99d75ff52765719d0cc2050630"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/b891e7a6bb06e0f6560e5932665ac660acd12225"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/c21afc7c216a4d257a4f3f300e0791890bc846b9"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/cb20da33839f28f590c99f16bafaa6151451c0e8"
}
],
"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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