{"id":"CVE-2026-31438","state":"PUBLISHED","title":"netfs: Fix kernel BUG in netfs_limit_iter() for ITER_KVEC iterators","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfs: Fix kernel BUG in netfs_limit_iter() for ITER_KVEC iterators\n\nWhen a process crashes and the kernel writes a core dump to a 9P\nfilesystem, __kernel_write() creates an ITER_KVEC iterator. This\niterator reaches netfs_limit_iter() via netfs_unbuffered_write(), which\nonly handles ITER_FOLIOQ, ITER_BVEC and ITER_XARRAY iterator types,\nhitting the BUG() for any other type.\n\nFix this by adding netfs_limit_kvec() following the same pattern as\nnetfs_limit_bvec(), since both kvec and bvec are simple segment arrays\nwith pointer and length fields. Dispatch it from netfs_limit_iter() when\nthe iterator type is ITER_KVEC.","publishedAt":"2026-04-22T13:53:37.053Z","updatedAt":"2026-05-11T22:08:42.611Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"cae932d3aee55035a54415dcea8e7ecf2ec469b5","status":"affected","lessThan":"18c2e20b42dd21db599e42d05ddaeeb647b2bb6d","versionType":"git"},{"version":"cae932d3aee55035a54415dcea8e7ecf2ec469b5","status":"affected","lessThan":"4bc2d72c7695cedf6d4e1a558924903c2b28a78e","versionType":"git"},{"version":"cae932d3aee55035a54415dcea8e7ecf2ec469b5","status":"affected","lessThan":"00d6df7115f6972370974212de9088087820802e","versionType":"git"},{"version":"cae932d3aee55035a54415dcea8e7ecf2ec469b5","status":"affected","lessThan":"67e467a11f62ff64ad219dc6aa5459e132c79d14","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/netfs/iterator.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.8","versionType":"semver"},{"version":"6.12.80","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.21","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.11","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/netfs/iterator.c"]}],"references":["https://git.kernel.org/stable/c/18c2e20b42dd21db599e42d05ddaeeb647b2bb6d","https://git.kernel.org/stable/c/4bc2d72c7695cedf6d4e1a558924903c2b28a78e","https://git.kernel.org/stable/c/00d6df7115f6972370974212de9088087820802e","https://git.kernel.org/stable/c/67e467a11f62ff64ad219dc6aa5459e132c79d14"],"weaknesses":[],"ingestedAt":"2026-10-29T20:11:40.391Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/31xxx/CVE-2026-31438.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-31438","state":"PUBLISHED","datePublished":"2026-04-22T13:53:37.053Z","dateUpdated":"2026-05-11T22:08:42.611Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-03-09T15:48:24.090Z"},"containers":{"cna":{"title":"netfs: Fix kernel BUG in netfs_limit_iter() for ITER_KVEC iterators","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfs: Fix kernel BUG in netfs_limit_iter() for ITER_KVEC iterators\n\nWhen a process crashes and the kernel writes a core dump to a 9P\nfilesystem, __kernel_write() creates an ITER_KVEC iterator. This\niterator reaches netfs_limit_iter() via netfs_unbuffered_write(), which\nonly handles ITER_FOLIOQ, ITER_BVEC and ITER_XARRAY iterator types,\nhitting the BUG() for any other type.\n\nFix this by adding netfs_limit_kvec() following the same pattern as\nnetfs_limit_bvec(), since both kvec and bvec are simple segment arrays\nwith pointer and length fields. Dispatch it from netfs_limit_iter() when\nthe iterator type is ITER_KVEC."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"cae932d3aee55035a54415dcea8e7ecf2ec469b5","status":"affected","lessThan":"18c2e20b42dd21db599e42d05ddaeeb647b2bb6d","versionType":"git"},{"version":"cae932d3aee55035a54415dcea8e7ecf2ec469b5","status":"affected","lessThan":"4bc2d72c7695cedf6d4e1a558924903c2b28a78e","versionType":"git"},{"version":"cae932d3aee55035a54415dcea8e7ecf2ec469b5","status":"affected","lessThan":"00d6df7115f6972370974212de9088087820802e","versionType":"git"},{"version":"cae932d3aee55035a54415dcea8e7ecf2ec469b5","status":"affected","lessThan":"67e467a11f62ff64ad219dc6aa5459e132c79d14","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/netfs/iterator.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.8","versionType":"semver"},{"version":"6.12.80","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.21","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.11","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/netfs/iterator.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/18c2e20b42dd21db599e42d05ddaeeb647b2bb6d"},{"url":"https://git.kernel.org/stable/c/4bc2d72c7695cedf6d4e1a558924903c2b28a78e"},{"url":"https://git.kernel.org/stable/c/00d6df7115f6972370974212de9088087820802e"},{"url":"https://git.kernel.org/stable/c/67e467a11f62ff64ad219dc6aa5459e132c79d14"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-05-11T22:08:42.611Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"6.12.80"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"6.18.21"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"6.19.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"7.0"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}