{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-72350", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-09T03:40:39.921Z", "datePublished": "2026-08-15T05:55:53.532Z", "dateUpdated": "2026-08-17T05:43:07.758Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:43:07.758Z" }, "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": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "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 (>=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>=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." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/netfilter/xt_u32.c" ], "versions": [ { "version": "1b50b8a371e90a5e110f466e4ac02cf6b5f681de", "lessThan": "ca7c92d9701249e6daf132087756a88cbf2bb2a3", "status": "affected", "versionType": "git" }, { "version": "1b50b8a371e90a5e110f466e4ac02cf6b5f681de", "lessThan": "b33b44250d57ab0e5a1e2571b5285fb0d0a7f382", "status": "affected", "versionType": "git" }, { "version": "1b50b8a371e90a5e110f466e4ac02cf6b5f681de", "lessThan": "728f479dc0447ae7eaef87926ff49142e415a811", "status": "affected", "versionType": "git" }, { "version": "1b50b8a371e90a5e110f466e4ac02cf6b5f681de", "lessThan": "0a8b7a6d763775709c601f584e709ae48bcc000a", "status": "affected", "versionType": "git" }, { "version": "1b50b8a371e90a5e110f466e4ac02cf6b5f681de", "lessThan": "cce42014415cecd98aa49b3950e7b02ee7c81268", "status": "affected", "versionType": "git" }, { "version": "1b50b8a371e90a5e110f466e4ac02cf6b5f681de", "lessThan": "a597a722fb71a534138c20359b655726622b5f17", "status": "affected", "versionType": "git" }, { "version": "1b50b8a371e90a5e110f466e4ac02cf6b5f681de", "lessThan": "00d034fe8230dfc5832fe011ff2d81c1a2cc7a29", "status": "affected", "versionType": "git" }, { "version": "1b50b8a371e90a5e110f466e4ac02cf6b5f681de", "lessThan": "64cdf7d30ac18e43df6c48004435febb965809a8", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/netfilter/xt_u32.c" ], "versions": [ { "version": "2.6.23", "status": "affected" }, { "version": "0", "lessThan": "2.6.23", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.261", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.212", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.178", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.97", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.23", "versionEndExcluding": "5.10.261" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.23", "versionEndExcluding": "5.15.212" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.23", "versionEndExcluding": "6.1.178" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.23", "versionEndExcluding": "6.6.145" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.23", "versionEndExcluding": "6.12.97" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.23", "versionEndExcluding": "6.18.40" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.23", "versionEndExcluding": "7.1.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.23", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/ca7c92d9701249e6daf132087756a88cbf2bb2a3" }, { "url": "https://git.kernel.org/stable/c/b33b44250d57ab0e5a1e2571b5285fb0d0a7f382" }, { "url": "https://git.kernel.org/stable/c/728f479dc0447ae7eaef87926ff49142e415a811" }, { "url": "https://git.kernel.org/stable/c/0a8b7a6d763775709c601f584e709ae48bcc000a" }, { "url": "https://git.kernel.org/stable/c/cce42014415cecd98aa49b3950e7b02ee7c81268" }, { "url": "https://git.kernel.org/stable/c/a597a722fb71a534138c20359b655726622b5f17" }, { "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": { "engine": "bippy-1.2.0" } } } }