FKIE_CVE-2026-64554
Vulnerability from fkie_nvd - Published: 2026-07-27 21:17 - Updated: 2026-07-30 06:25
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
netfilter: bridge: fix stale prevhdr pointer in br_ip6_fragment()
br_ip6_fragment() gets prevhdr, a pointer into the skb head, from
ip6_find_1stfragopt(), then calls skb_checksum_help(). For a cloned skb
skb_checksum_help() reallocates the head via pskb_expand_head(), leaving
prevhdr dangling. It is later dereferenced in ip6_frag_next(), causing a
use-after-free write.
Save prevhdr's offset before skb_checksum_help() and recompute it after,
like commit ef0efcd3bd3f ("ipv6: Fix dangling pointer when ipv6
fragment").
BUG: KASAN: slab-use-after-free in ip6_frag_next (net/ipv6/ip6_output.c:857)
Write of size 1 at addr ffff888013ff5016 by task exploit/141
Call Trace:
...
kasan_report (mm/kasan/report.c:595)
ip6_frag_next (net/ipv6/ip6_output.c:857)
br_ip6_fragment (net/ipv6/netfilter.c:212)
nf_ct_bridge_post (net/bridge/netfilter/nf_conntrack_bridge.c:407)
nf_hook_slow (net/netfilter/core.c:619)
br_forward_finish (net/bridge/br_forward.c:66)
__br_forward (net/bridge/br_forward.c:115)
maybe_deliver (net/bridge/br_forward.c:191)
br_flood (net/bridge/br_forward.c:245)
br_handle_frame_finish (net/bridge/br_input.c:229)
br_handle_frame (net/bridge/br_input.c:442)
...
packet_sendmsg (net/packet/af_packet.c:3114)
...
do_syscall_64 (arch/x86/entry/syscall_64.c:94)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
Kernel panic - not syncing: Fatal exception in interrupt
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/ipv6/netfilter.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "8c10778ec674b67a07ea042fcba64270f3f38a5a",
"status": "affected",
"version": "764dd163ac922f8683b5bcd3007251ce7b26cd33",
"versionType": "git"
},
{
"lessThan": "2731efa6364e47934c96eb69e01ea131e8af8030",
"status": "affected",
"version": "764dd163ac922f8683b5bcd3007251ce7b26cd33",
"versionType": "git"
},
{
"lessThan": "00c06ef8c018493943891a7d0ca82b71b24f3180",
"status": "affected",
"version": "764dd163ac922f8683b5bcd3007251ce7b26cd33",
"versionType": "git"
},
{
"lessThan": "c141f69d0a0fb16964dbc293650047e69bda8af7",
"status": "affected",
"version": "764dd163ac922f8683b5bcd3007251ce7b26cd33",
"versionType": "git"
},
{
"lessThan": "f2e6596d10783557aeb9668da2a3b4d19deb2001",
"status": "affected",
"version": "764dd163ac922f8683b5bcd3007251ce7b26cd33",
"versionType": "git"
},
{
"lessThan": "1c4f67c89fd27c4df4c70b135c2c59627698b3c0",
"status": "affected",
"version": "764dd163ac922f8683b5bcd3007251ce7b26cd33",
"versionType": "git"
},
{
"lessThan": "4ac981a8b7ce7aec99a52d08f8a8953e8e120067",
"status": "affected",
"version": "764dd163ac922f8683b5bcd3007251ce7b26cd33",
"versionType": "git"
},
{
"lessThan": "86f3ce81dd2b4b0aa2c3016c989a943e4b1b643d",
"status": "affected",
"version": "764dd163ac922f8683b5bcd3007251ce7b26cd33",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/ipv6/netfilter.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "5.3"
},
{
"lessThan": "5.3",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.261",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.212",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.178",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.145",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.97",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.40",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.5",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2-rc4",
"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: bridge: fix stale prevhdr pointer in br_ip6_fragment()\n\nbr_ip6_fragment() gets prevhdr, a pointer into the skb head, from\nip6_find_1stfragopt(), then calls skb_checksum_help(). For a cloned skb\nskb_checksum_help() reallocates the head via pskb_expand_head(), leaving\nprevhdr dangling. It is later dereferenced in ip6_frag_next(), causing a\nuse-after-free write.\n\nSave prevhdr\u0027s offset before skb_checksum_help() and recompute it after,\nlike commit ef0efcd3bd3f (\"ipv6: Fix dangling pointer when ipv6\nfragment\").\n\n BUG: KASAN: slab-use-after-free in ip6_frag_next (net/ipv6/ip6_output.c:857)\n Write of size 1 at addr ffff888013ff5016 by task exploit/141\n Call Trace:\n ...\n kasan_report (mm/kasan/report.c:595)\n ip6_frag_next (net/ipv6/ip6_output.c:857)\n br_ip6_fragment (net/ipv6/netfilter.c:212)\n nf_ct_bridge_post (net/bridge/netfilter/nf_conntrack_bridge.c:407)\n nf_hook_slow (net/netfilter/core.c:619)\n br_forward_finish (net/bridge/br_forward.c:66)\n __br_forward (net/bridge/br_forward.c:115)\n maybe_deliver (net/bridge/br_forward.c:191)\n br_flood (net/bridge/br_forward.c:245)\n br_handle_frame_finish (net/bridge/br_input.c:229)\n br_handle_frame (net/bridge/br_input.c:442)\n ...\n packet_sendmsg (net/packet/af_packet.c:3114)\n ...\n do_syscall_64 (arch/x86/entry/syscall_64.c:94)\n entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)\n Kernel panic - not syncing: Fatal exception in interrupt"
}
],
"id": "CVE-2026-64554",
"lastModified": "2026-07-30T06:25:59.110",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "ADJACENT_NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 8.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 2.8,
"impactScore": 5.9,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-07-27T21:17:08.437",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/00c06ef8c018493943891a7d0ca82b71b24f3180"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/1c4f67c89fd27c4df4c70b135c2c59627698b3c0"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/2731efa6364e47934c96eb69e01ea131e8af8030"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/4ac981a8b7ce7aec99a52d08f8a8953e8e120067"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/86f3ce81dd2b4b0aa2c3016c989a943e4b1b643d"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/8c10778ec674b67a07ea042fcba64270f3f38a5a"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/c141f69d0a0fb16964dbc293650047e69bda8af7"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/f2e6596d10783557aeb9668da2a3b4d19deb2001"
}
],
"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.
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