{"api_version":"1","generated_at":"2026-06-25T11:33:15+00:00","cve":"CVE-2026-53267","urls":{"html":"https://cve.report/CVE-2026-53267","api":"https://cve.report/api/cve/CVE-2026-53267.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-53267","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-53267"},"summary":{"title":"netfilter: nft_ct: bail out on template ct in get eval","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_ct: bail out on template ct in get eval\n\nI noticed this issue while looking at a historic syzbot report [1].\n\nA rule like the one below is enough to trigger the bug:\n\n    table ip t {\n        chain pre {\n            type filter hook prerouting priority raw;\n            ct zone set 1\n            ct original saddr 1.2.3.4 accept\n        }\n    }\n\nThe first expression attaches a per-cpu template ct via\nnft_ct_set_zone_eval() (nf_ct_tmpl_alloc -> kzalloc, tuple is all\nzero, nf_ct_l3num(ct) == 0). The next expression then calls\nnft_ct_get_eval() on the same skb, treats the template as a real ct\nand hits the 16-byte memcpy path. With dreg at NFT_REG32_15 this\noverflows past struct nft_regs on the kernel stack; with smaller\ndreg values it silently clobbers adjacent registers.\n\nReject template ct at the eval entry and in nft_ct_get_fast_eval(),\nmirroring the check nft_ct_set_eval() already has. Additionally,\nbound the address copy in NFT_CT_SRC / NFT_CT_DST by priv->len\ninstead of by nf_ct_l3num(ct): nf_ct_get_tuple() zeroes the tuple\nbefore pkt_to_tuple() fills in only the protocol-relevant leading\nbytes, so the trailing bytes of tuple->{src,dst}.u3.all are\nwell-defined zero. priv->len is validated at rule load, so the\ncopy size is now bounded by the destination register rather than\nby an untrusted field on the conntrack.\n\n[1]: https://syzkaller.appspot.com/bug?id=389cf09cb72926114fce90dc85a2c3231dcb647c","state":"PUBLISHED","assigner":"Linux","published_at":"2026-06-25 09:16:44","updated_at":"2026-06-25 09:16:44"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/8470f676eadeab99132708acb1a85915664d6115","name":"https://git.kernel.org/stable/c/8470f676eadeab99132708acb1a85915664d6115","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f071b0bf078146368d18e4eec386bf2ddc0ab7e0","name":"https://git.kernel.org/stable/c/f071b0bf078146368d18e4eec386bf2ddc0ab7e0","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2e154b5f53f1b0b490c7b8b02499f90feb86b1d5","name":"https://git.kernel.org/stable/c/2e154b5f53f1b0b490c7b8b02499f90feb86b1d5","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/3027ecbdb5fdf9200251c21d4818e4c447ef78e1","name":"https://git.kernel.org/stable/c/3027ecbdb5fdf9200251c21d4818e4c447ef78e1","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/af80f78ce984649e1698b841cd33f4fa505ad828","name":"https://git.kernel.org/stable/c/af80f78ce984649e1698b841cd33f4fa505ad828","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-53267","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53267","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 45d9bcda21f4c13be75e3571b0f0ef39e77934b5 af80f78ce984649e1698b841cd33f4fa505ad828 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 45d9bcda21f4c13be75e3571b0f0ef39e77934b5 8470f676eadeab99132708acb1a85915664d6115 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 45d9bcda21f4c13be75e3571b0f0ef39e77934b5 f071b0bf078146368d18e4eec386bf2ddc0ab7e0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 45d9bcda21f4c13be75e3571b0f0ef39e77934b5 2e154b5f53f1b0b490c7b8b02499f90feb86b1d5 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 45d9bcda21f4c13be75e3571b0f0ef39e77934b5 3027ecbdb5fdf9200251c21d4818e4c447ef78e1 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4.1","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 4.1 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.143 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.94 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.36 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0.13 7.0.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/netfilter/nft_ct.c","net/netfilter/nft_ct_fast.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"af80f78ce984649e1698b841cd33f4fa505ad828","status":"affected","version":"45d9bcda21f4c13be75e3571b0f0ef39e77934b5","versionType":"git"},{"lessThan":"8470f676eadeab99132708acb1a85915664d6115","status":"affected","version":"45d9bcda21f4c13be75e3571b0f0ef39e77934b5","versionType":"git"},{"lessThan":"f071b0bf078146368d18e4eec386bf2ddc0ab7e0","status":"affected","version":"45d9bcda21f4c13be75e3571b0f0ef39e77934b5","versionType":"git"},{"lessThan":"2e154b5f53f1b0b490c7b8b02499f90feb86b1d5","status":"affected","version":"45d9bcda21f4c13be75e3571b0f0ef39e77934b5","versionType":"git"},{"lessThan":"3027ecbdb5fdf9200251c21d4818e4c447ef78e1","status":"affected","version":"45d9bcda21f4c13be75e3571b0f0ef39e77934b5","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/netfilter/nft_ct.c","net/netfilter/nft_ct_fast.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"4.1"},{"lessThan":"4.1","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.143","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.94","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.36","versionType":"semver"},{"lessThanOrEqual":"7.0.*","status":"unaffected","version":"7.0.13","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.143","versionStartIncluding":"4.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.94","versionStartIncluding":"4.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.36","versionStartIncluding":"4.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0.13","versionStartIncluding":"4.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1","versionStartIncluding":"4.1","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_ct: bail out on template ct in get eval\n\nI noticed this issue while looking at a historic syzbot report [1].\n\nA rule like the one below is enough to trigger the bug:\n\n    table ip t {\n        chain pre {\n            type filter hook prerouting priority raw;\n            ct zone set 1\n            ct original saddr 1.2.3.4 accept\n        }\n    }\n\nThe first expression attaches a per-cpu template ct via\nnft_ct_set_zone_eval() (nf_ct_tmpl_alloc -> kzalloc, tuple is all\nzero, nf_ct_l3num(ct) == 0). The next expression then calls\nnft_ct_get_eval() on the same skb, treats the template as a real ct\nand hits the 16-byte memcpy path. With dreg at NFT_REG32_15 this\noverflows past struct nft_regs on the kernel stack; with smaller\ndreg values it silently clobbers adjacent registers.\n\nReject template ct at the eval entry and in nft_ct_get_fast_eval(),\nmirroring the check nft_ct_set_eval() already has. Additionally,\nbound the address copy in NFT_CT_SRC / NFT_CT_DST by priv->len\ninstead of by nf_ct_l3num(ct): nf_ct_get_tuple() zeroes the tuple\nbefore pkt_to_tuple() fills in only the protocol-relevant leading\nbytes, so the trailing bytes of tuple->{src,dst}.u3.all are\nwell-defined zero. priv->len is validated at rule load, so the\ncopy size is now bounded by the destination register rather than\nby an untrusted field on the conntrack.\n\n[1]: https://syzkaller.appspot.com/bug?id=389cf09cb72926114fce90dc85a2c3231dcb647c"}],"providerMetadata":{"dateUpdated":"2026-06-25T08:39:53.852Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/af80f78ce984649e1698b841cd33f4fa505ad828"},{"url":"https://git.kernel.org/stable/c/8470f676eadeab99132708acb1a85915664d6115"},{"url":"https://git.kernel.org/stable/c/f071b0bf078146368d18e4eec386bf2ddc0ab7e0"},{"url":"https://git.kernel.org/stable/c/2e154b5f53f1b0b490c7b8b02499f90feb86b1d5"},{"url":"https://git.kernel.org/stable/c/3027ecbdb5fdf9200251c21d4818e4c447ef78e1"}],"title":"netfilter: nft_ct: bail out on template ct in get eval","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-53267","datePublished":"2026-06-25T08:39:53.852Z","dateReserved":"2026-06-09T07:44:35.395Z","dateUpdated":"2026-06-25T08:39:53.852Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-06-25 09:16:44","lastModifiedDate":"2026-06-25 09:16:44","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"53267","Ordinal":"1","Title":"netfilter: nft_ct: bail out on template ct in get eval","CVE":"CVE-2026-53267","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"53267","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_ct: bail out on template ct in get eval\n\nI noticed this issue while looking at a historic syzbot report [1].\n\nA rule like the one below is enough to trigger the bug:\n\n    table ip t {\n        chain pre {\n            type filter hook prerouting priority raw;\n            ct zone set 1\n            ct original saddr 1.2.3.4 accept\n        }\n    }\n\nThe first expression attaches a per-cpu template ct via\nnft_ct_set_zone_eval() (nf_ct_tmpl_alloc -> kzalloc, tuple is all\nzero, nf_ct_l3num(ct) == 0). The next expression then calls\nnft_ct_get_eval() on the same skb, treats the template as a real ct\nand hits the 16-byte memcpy path. With dreg at NFT_REG32_15 this\noverflows past struct nft_regs on the kernel stack; with smaller\ndreg values it silently clobbers adjacent registers.\n\nReject template ct at the eval entry and in nft_ct_get_fast_eval(),\nmirroring the check nft_ct_set_eval() already has. Additionally,\nbound the address copy in NFT_CT_SRC / NFT_CT_DST by priv->len\ninstead of by nf_ct_l3num(ct): nf_ct_get_tuple() zeroes the tuple\nbefore pkt_to_tuple() fills in only the protocol-relevant leading\nbytes, so the trailing bytes of tuple->{src,dst}.u3.all are\nwell-defined zero. priv->len is validated at rule load, so the\ncopy size is now bounded by the destination register rather than\nby an untrusted field on the conntrack.\n\n[1]: https://syzkaller.appspot.com/bug?id=389cf09cb72926114fce90dc85a2c3231dcb647c","Type":"Description","Title":"netfilter: nft_ct: bail out on template ct in get eval"}]}}}