{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2026-98541", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-98541", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-10-18T15:18:09.190Z", "updatedAt": "2026-10-19T09:21:24.620Z", "importedAt": "2026-10-24T01:58:41.756Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "fou: reject omitted FOU_ATTR_IPPROTO on FOU_ENCAP_DIRECT", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nfou: reject omitted FOU_ATTR_IPPROTO on FOU_ENCAP_DIRECT\n\nCommit 7a9bc9e3f423 (\"fou: Don't allow 0 for FOU_ATTR_IPPROTO.\") added\nNLA_POLICY_MIN(NLA_U8, 1) to fou_nl_policy[FOU_ATTR_IPPROTO], which\nrejects an explicitly supplied FOU_ATTR_IPPROTO == 0 attribute with\n-ERANGE.\n\nHowever, FOU_ATTR_IPPROTO is an optional netlink attribute. When a user\nsends FOU_CMD_ADD with FOU_ATTR_TYPE set to FOU_ENCAP_DIRECT and omits\nFOU_ATTR_IPPROTO entirely, nla_policy validation succeeds and\nparse_nl_config() leaves cfg->protocol as 0 (from memset(cfg, 0,\nsizeof(*cfg))). fou_create() then creates a FOU_ENCAP_DIRECT socket with\nfou->protocol == 0.\n\nIn fou_udp_recv(), returning -fou->protocol to udp_queue_rcv_one_skb()\ntriggers IP protocol resubmission when fou->protocol > 0, whereas\nreturning 0 tells the UDP tunnel layer that the skb was consumed without\nfreeing it. When fou->protocol == 0, every packet received on the socket\nreturns 0 from fou_udp_recv() and leaks the sk_buff.\n\nReject FOU_ENCAP_DIRECT when !cfg->protocol in fou_create() so that\ncreating a direct encapsulation port without FOU_ATTR_IPPROTO fails with\n-EINVAL while leaving FOU_CMD_DEL and FOU_CMD_GET (which share\nparse_nl_config()) unaffected.\n\nTested in QEMU against Linux 7.3.0-rc3 by sending a FOU_CMD_ADD Generic\nNetlink request with FOU_ATTR_PORT = 5555 and FOU_ATTR_TYPE =\nFOU_ENCAP_DIRECT while omitting FOU_ATTR_IPPROTO. On the unfixed kernel,\nFOU_CMD_ADD succeeds (err = 0), FOU_CMD_GET reports fou->type = 1 and\nfou->protocol = 0, and sending 4000 UDP packets to 127.0.0.1:5555 leaks\nall 4000 sk_buffs (SUnreclaim in /proc/meminfo grows from 41456 kB to\n59008 kB, +17552 kB); with this patch applied, FOU_CMD_ADD is rejected\nwith -EINVAL (-22).", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "23461551c00628c3f3fe9cf837bf53cf8f212b63", "status": "affected", "versionType": "git", "lessThan": "fd20220f86947d66d4dba2d76f13a28dbd86ef30" }, { "version": "23461551c00628c3f3fe9cf837bf53cf8f212b63", "status": "affected", "versionType": "git", "lessThan": "46b1ffb7e169c7e401dd890b29e55dbc261f8f01" }, { "version": "23461551c00628c3f3fe9cf837bf53cf8f212b63", "status": "affected", "versionType": "git", "lessThan": "7f4ba56f5d310dd018972916167985010a5d66a1" }, { "version": "23461551c00628c3f3fe9cf837bf53cf8f212b63", "status": "affected", "versionType": "git", "lessThan": "3bcc1624cc1cdcc05b566475d6e848093ab2a8f6" }, { "version": "23461551c00628c3f3fe9cf837bf53cf8f212b63", "status": "affected", "versionType": "git", "lessThan": "8b43f40798bb2758489fbbcae7e841ad4443c213" }, { "version": "23461551c00628c3f3fe9cf837bf53cf8f212b63", "status": "affected", "versionType": "git", "lessThan": "b1229b210ef5a39c58be665e6798203751411842" }, { "version": "23461551c00628c3f3fe9cf837bf53cf8f212b63", "status": "affected", "versionType": "git", "lessThan": "520cf06b8ea0ba5bcc1b8b982ef07f02b5e56221" }, { "version": "23461551c00628c3f3fe9cf837bf53cf8f212b63", "status": "affected", "versionType": "git", "lessThan": "d22609f3d13fc5baacd92c222731b03c593401db" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "3.18", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "3.18" }, { "version": "5.10.271", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.15.222", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.189", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.158", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.112", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.55", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "7.2.9", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "7.2.*" }, { "version": "7.3", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }