CVE-2026-72350 (GCVE-0-2026-72350)
Vulnerability from cvelistv5 – Published: 2026-08-15 05:55 – Updated: 2026-08-17 05:43
VLAI
EPSS
VEX
Title
netfilter: xt_u32: reject invalid shift counts
Summary
In the Linux kernel, the following vulnerability has been resolved:
netfilter: xt_u32: reject invalid shift counts
u32_match_it() executes rule-supplied shift operands on a 32-bit
value. A malformed u32 rule can provide a shift count of 32 or more,
triggering an undefined shift out-of-bounds during packet evaluation.
Validate XT_U32_LEFTSH and XT_U32_RIGHTSH operands in
u32_mt_checkentry() and reject malformed rules before they reach the
packet path.
Severity
7.8 (High)
Assigner
References
8 references
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
1b50b8a371e90a5e110f466e4ac02cf6b5f681de , < ca7c92d9701249e6daf132087756a88cbf2bb2a3
(git)
Affected: 1b50b8a371e90a5e110f466e4ac02cf6b5f681de , < b33b44250d57ab0e5a1e2571b5285fb0d0a7f382 (git) Affected: 1b50b8a371e90a5e110f466e4ac02cf6b5f681de , < 728f479dc0447ae7eaef87926ff49142e415a811 (git) Affected: 1b50b8a371e90a5e110f466e4ac02cf6b5f681de , < 0a8b7a6d763775709c601f584e709ae48bcc000a (git) Affected: 1b50b8a371e90a5e110f466e4ac02cf6b5f681de , < cce42014415cecd98aa49b3950e7b02ee7c81268 (git) Affected: 1b50b8a371e90a5e110f466e4ac02cf6b5f681de , < a597a722fb71a534138c20359b655726622b5f17 (git) Affected: 1b50b8a371e90a5e110f466e4ac02cf6b5f681de , < 00d034fe8230dfc5832fe011ff2d81c1a2cc7a29 (git) Affected: 1b50b8a371e90a5e110f466e4ac02cf6b5f681de , < 64cdf7d30ac18e43df6c48004435febb965809a8 (git) |
guessed | |
| Linux | Linux |
Affected:
2.6.23
Unaffected: 0 , < 2.6.23 (semver) Unaffected: 5.10.261 , ≤ 5.10.* (semver) Unaffected: 5.15.212 , ≤ 5.15.* (semver) Unaffected: 6.1.178 , ≤ 6.1.* (semver) Unaffected: 6.6.145 , ≤ 6.6.* (semver) Unaffected: 6.12.97 , ≤ 6.12.* (semver) Unaffected: 6.18.40 , ≤ 6.18.* (semver) Unaffected: 7.1.5 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix) |
guessed |
{
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"product": "Linux",
"programFiles": [
"net/netfilter/xt_u32.c"
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"version": "0",
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},
{
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"status": "unaffected",
"version": "5.10.261",
"versionType": "semver"
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{
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"version": "5.15.212",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "6.1.178",
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{
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"versionType": "semver"
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{
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"status": "unaffected",
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},
{
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"status": "unaffected",
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"versionType": "semver"
},
{
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"status": "unaffected",
"version": "7.1.5",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
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],
"cpeApplicability": [
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],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: xt_u32: reject invalid shift counts\n\nu32_match_it() executes rule-supplied shift operands on a 32-bit\nvalue. A malformed u32 rule can provide a shift count of 32 or more,\ntriggering an undefined shift out-of-bounds during packet evaluation.\n\nValidate XT_U32_LEFTSH and XT_U32_RIGHTSH operands in\nu32_mt_checkentry() and reject malformed rules before they reach the\npacket path."
}
],
"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"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - Malicious xt_u32 match rules are installed via IPT_SO_SET_REPLACE setsockopt or nftables NFNetlink (nft_compat match); per kernel CNA guidance netfilter/xtables rule setup is Local even though installed rules evaluate on ingress/egress packets through ipt_do_table.\nAC:L - The attacker fully controls XT_U32_LEFTSH/RIGHTSH shift operands (\u003e=32) in matchinfo and can send triggering packets through the hooked netfilter chain; no race or uncontrollable victim state is required.\nPR:L - Installing xt_u32 iptables/nftables rules requires CAP_NET_ADMIN, obtainable by unprivileged users in user/network namespaces via unshare -Urn; ip_tables.c and nfnetlink enforce ns_capable/netlink_net_capable against the namespace user_ns.\nUI:N - The attacker installs the malicious u32 match rule and generates matching traffic in their namespace; no separate victim action (opening files, mounting media, clicking links) is needed.\nS:U - Undefined shift during xt_u32 packet matching and any resulting kernel crash remain within the host kernel security authority; this is standard local kernel compromise, not a VM escape or sandbox boundary crossing.\nC:H - Undefined-behavior shifts on packet-derived u32 values corrupt val and @ offset accumulation, driving attacker-influenced skb_copy_bits reads at unintended offsets; per CNA guidance exploitable kernel memory-unsafe arithmetic warrants High confidentiality.\nI:H - Invalid shift counts corrupt val/at control flow in the u32_match_it hot path; C11 undefined behavior in kernel netfilter matching is exploitable for integrity compromise and potential code execution per CNA memory-corruption guidance.\nA:H - Evaluating a malformed xt_u32 rule with shift\u003e=32 triggers undefined shift-out-of-bounds during packet matching; vulnerable kernels also BUG() on skb_copy_bits failure, provoking kernel panic/oops during rule evaluation."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T05:43:07.758Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
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"url": "https://git.kernel.org/stable/c/ca7c92d9701249e6daf132087756a88cbf2bb2a3"
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{
"url": "https://git.kernel.org/stable/c/b33b44250d57ab0e5a1e2571b5285fb0d0a7f382"
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{
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{
"url": "https://git.kernel.org/stable/c/0a8b7a6d763775709c601f584e709ae48bcc000a"
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"url": "https://git.kernel.org/stable/c/00d034fe8230dfc5832fe011ff2d81c1a2cc7a29"
},
{
"url": "https://git.kernel.org/stable/c/64cdf7d30ac18e43df6c48004435febb965809a8"
}
],
"title": "netfilter: xt_u32: reject invalid shift counts",
"x_generator": {
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"cveMetadata": {
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"assignerShortName": "Linux",
"cveId": "CVE-2026-72350",
"datePublished": "2026-08-15T05:55:53.532Z",
"dateReserved": "2026-08-09T03:40:39.921Z",
"dateUpdated": "2026-08-17T05:43:07.758Z",
"state": "PUBLISHED"
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"dataType": "CVE_RECORD",
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"epss": "0.00176",
"percentile": "0.06377"
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"nvd": {
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"version": "0",
"versionType": "semver"
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"status": "unaffected",
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{
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{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.178",
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{
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{
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"version": "6.18.40",
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{
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"status": "unaffected",
"version": "7.1.5",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
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}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: xt_u32: reject invalid shift counts\n\nu32_match_it() executes rule-supplied shift operands on a 32-bit\nvalue. A malformed u32 rule can provide a shift count of 32 or more,\ntriggering an undefined shift out-of-bounds during packet evaluation.\n\nValidate XT_U32_LEFTSH and XT_U32_RIGHTSH operands in\nu32_mt_checkentry() and reject malformed rules before they reach the\npacket path."
}
],
"id": "CVE-2026-72350",
"lastModified": "2026-08-17T06:18:39.020",
"metrics": {
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{
"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": "2026-08-15T06:22:08.407",
"references": [
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}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
},
"redhat_vex": {
"aggregate_severity": "Low",
"current_release_date": "2026-08-19T17:16:17+00:00",
"cve": "CVE-2026-72350",
"id": "CVE-2026-72350",
"initial_release_date": "2026-08-15T00:00:00+00:00",
"product_status:known_affected": "166",
"product_status:known_not_affected": "108",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "kernel: netfilter: xt_u32: reject invalid shift counts",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72350.json",
"version": "3"
},
"suse_vex": {
"aggregate_severity": "low",
"current_release_date": "2026-09-22T16:38:25Z",
"cve": "CVE-2026-72350",
"id": "CVE-2026-72350",
"initial_release_date": "2026-09-01T13:29:41Z",
"product_status:first_fixed": "60",
"product_status:known_affected": "362",
"source": "SUSE CSAF VEX",
"status": "interim",
"title": "SUSE CVE CVE-2026-72350",
"url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-72350.json",
"version": "5"
}
}
}
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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.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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