{"id":"CVE-2026-53218","state":"PUBLISHED","title":"netfilter: nft_exthdr: fix register tracking for F_PRESENT flag","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_exthdr: fix register tracking for F_PRESENT flag\n\nnft_exthdr_init() passes user-controlled priv->len to\nnft_parse_register_store(), which marks that many bytes in the\nregister bitmap as initialized.  However, when NFT_EXTHDR_F_PRESENT\nis set, the eval paths write only 1 byte (nft_reg_store8) or\n4 bytes (*dest = 0 on TCP/DCCP error path).  When len > 4,\nregisters beyond the first are never written, retaining\nuninitialized stack data from nft_regs.\n\nBail out if userspace requests too much data when F_PRESENT is set.","publishedAt":"2026-06-25T08:39:21.069Z","updatedAt":"2026-10-15T01:22:43.516Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"c078ca3b0c5bf82c2b31906c446d6e2ad8ea0783","status":"affected","lessThan":"8738b1b6d0e639ca1fc0f61516afd3557ac4ecc6","versionType":"git"},{"version":"c078ca3b0c5bf82c2b31906c446d6e2ad8ea0783","status":"affected","lessThan":"19748967d59c31d24d21d40b728570788310b237","versionType":"git"},{"version":"c078ca3b0c5bf82c2b31906c446d6e2ad8ea0783","status":"affected","lessThan":"46fc15a044e9938e7ea77786fb37edd2cd74f031","versionType":"git"},{"version":"c078ca3b0c5bf82c2b31906c446d6e2ad8ea0783","status":"affected","lessThan":"cd513e43b4b2bd1de39e2367bc4261c699a8652f","versionType":"git"},{"version":"c078ca3b0c5bf82c2b31906c446d6e2ad8ea0783","status":"affected","lessThan":"67b27434c43b68a97becda98c9f0c8cf6cba2134","versionType":"git"},{"version":"c078ca3b0c5bf82c2b31906c446d6e2ad8ea0783","status":"affected","lessThan":"78069a6d8bc86c9e036eb82c2af4a19cc1871a53","versionType":"git"},{"version":"c078ca3b0c5bf82c2b31906c446d6e2ad8ea0783","status":"affected","lessThan":"f08fb3d42fd3aad0b7a263da3ac3ebaf0845e265","versionType":"git"},{"version":"c078ca3b0c5bf82c2b31906c446d6e2ad8ea0783","status":"affected","lessThan":"772cecf198da732faebb5dcfc46d66a505be8495","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/nft_exthdr.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.11","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.11","versionType":"semver"},{"version":"5.10.259","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.210","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.176","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.143","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.94","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.36","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.13","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/nft_exthdr.c"]}],"references":["https://git.kernel.org/stable/c/8738b1b6d0e639ca1fc0f61516afd3557ac4ecc6","https://git.kernel.org/stable/c/19748967d59c31d24d21d40b728570788310b237","https://git.kernel.org/stable/c/46fc15a044e9938e7ea77786fb37edd2cd74f031","https://git.kernel.org/stable/c/cd513e43b4b2bd1de39e2367bc4261c699a8652f","https://git.kernel.org/stable/c/67b27434c43b68a97becda98c9f0c8cf6cba2134","https://git.kernel.org/stable/c/78069a6d8bc86c9e036eb82c2af4a19cc1871a53","https://git.kernel.org/stable/c/f08fb3d42fd3aad0b7a263da3ac3ebaf0845e265","https://git.kernel.org/stable/c/772cecf198da732faebb5dcfc46d66a505be8495","https://cert-portal.siemens.com/productcert/html/ssa-019113.html","https://cert-portal.siemens.com/productcert/html/ssa-457936.html","https://cert-portal.siemens.com/productcert/html/ssa-784472.html"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:16.098Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/53xxx/CVE-2026-53218.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-53218","state":"PUBLISHED","datePublished":"2026-06-25T08:39:21.069Z","dateUpdated":"2026-10-15T01:22:43.516Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-06-09T07:44:35.392Z"},"containers":{"cna":{"title":"netfilter: nft_exthdr: fix register tracking for F_PRESENT flag","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_exthdr: fix register tracking for F_PRESENT flag\n\nnft_exthdr_init() passes user-controlled priv->len to\nnft_parse_register_store(), which marks that many bytes in the\nregister bitmap as initialized.  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