CVE-2026-64414 (GCVE-0-2026-64414)
Vulnerability from cvelistv5
Published
2026-07-25 08:50
Modified
2026-08-17 04:55
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
netfilter: handle unreadable frags
sashiko reports:
When an skb with unreadable fragments (such as from devmem TCP, where
skb_frags_readable(skb) returns false) is processed by the u32 module,
skb_copy_bits() will safely return a negative error code [..]
xt_u32: bail out with hotdrop in this case.
gather_frags: return -1, just as if we had no fragment header.
nfnetlink_queue: restrict to the linear part.
nfnetlink_log: restrict to the linear part.
v2:
- skb_zerocopy helpers don't copy readable flag, i.e. nfnetlink_queue
is broken too
xt_u32 shouldn't return true if hotdrop was set.
References
| URL | Tags | |
|---|---|---|
Impacted products
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"net/netfilter/nfnetlink_log.c",
"net/netfilter/nfnetlink_queue.c",
"net/netfilter/xt_u32.c"
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"net/netfilter/nfnetlink_log.c",
"net/netfilter/nfnetlink_queue.c",
"net/netfilter/xt_u32.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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"version": "6.12"
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"status": "unaffected",
"version": "0",
"versionType": "semver"
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{
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"status": "unaffected",
"version": "6.12.96",
"versionType": "semver"
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{
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"version": "6.18.39",
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"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: handle unreadable frags\n\nsashiko reports:\n When an skb with unreadable fragments (such as from devmem TCP, where\n skb_frags_readable(skb) returns false) is processed by the u32 module,\n skb_copy_bits() will safely return a negative error code [..]\n\nxt_u32: bail out with hotdrop in this case.\ngather_frags: return -1, just as if we had no fragment header.\nnfnetlink_queue: restrict to the linear part.\nnfnetlink_log: restrict to the linear part.\n\nv2:\n - skb_zerocopy helpers don\u0027t copy readable flag, i.e. nfnetlink_queue\n is broken too\n xt_u32 shouldn\u0027t return true if hotdrop was set."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.5,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - Unreadable skbs arise on the receive side of device-memory TCP, and a remote peer can send packets that traverse netfilter hooks into u32, NFLOG, NFQUEUE, or IPv6 conntrack defragmentation. No local access is required in a network-exposed devmem TCP deployment.\nAC:L - Once devmem/header-split RX and an affected netfilter path are active, a sufficiently long payload or crafted IPv6 extension/fragment layout reliably reaches unreadable fragments. There is no race or condition the attacker must win, and triggering packets can be sent repeatedly.\nPR:N - The triggering packets are processed before application authentication, so the remote peer needs no account or kernel capability. CAP_NET_ADMIN is required for the operator\u0027s device and netfilter configuration, not for the attacker sending packets.\nUI:N - Packet reception and netfilter processing occur automatically without any victim action after the service and policy are configured.\nS:U - The resulting failure affects the same host kernel and does not cross a VM, IOMMU, or other distinct security authority boundary.\nC:N - skb_copy_bits() rejects the unreadable fragments before accessing their contents, while the NFQUEUE flag-loss path reaches an invalid page mapping. No attacker-accessible information-disclosure primitive was identified.\nI:N - The vulnerability causes BUG or invalid-access paths but provides no out-of-bounds write, use-after-free, type confusion, or attacker-controlled data modification.\nA:H - The u32, NFLOG, and IPv6 paths execute BUG(), and the NFQUEUE path can dereference an invalid page during netlink recvmsg. These can produce a kernel oops or panic and can be triggered repeatedly."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T04:55:13.439Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
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"references": [
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"url": "https://git.kernel.org/stable/c/3b13e7635795394705920cca1e1db7e4ca2e334b"
},
{
"url": "https://git.kernel.org/stable/c/fc5bfe63bacf8a3ae307b62b34206406ca733354"
},
{
"url": "https://git.kernel.org/stable/c/57056be3ec12e7d9ecd20a60d4060f510e4f284c"
},
{
"url": "https://git.kernel.org/stable/c/da5b58478a9c1b85608c9e40a3b8432d071b409e"
}
],
"title": "netfilter: handle unreadable frags",
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"cveId": "CVE-2026-64414",
"datePublished": "2026-07-25T08:50:54.495Z",
"dateReserved": "2026-07-19T15:36:31.786Z",
"dateUpdated": "2026-08-17T04:55:13.439Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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