{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-72379","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-08-09T03:40:39.922Z","datePublished":"2026-08-15T05:56:12.251Z","dateUpdated":"2026-08-17T05:13:31.893Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-17T05:13:31.893Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nfs: refuse O_TMPFILE creation with an unmapped fsuid or fsgid\n\nvfs_tmpfile() never checked that the caller's fsuid and fsgid map into\nthe filesystem.  On an idmapped mount whose idmapping does not cover the\ncaller's fs{u,g}id, the ->tmpfile() instance initializes the new inode\nthrough inode_init_owner(), where mapped_fsuid()/mapped_fsgid() return\nINVALID_UID/INVALID_GID, and the tmpfile ends up owned by (uid_t)-1.\n\nEvery other creation path already refuses this: may_o_create() (O_CREAT)\nand may_create_dentry() (mkdir, mknod, symlink, link) bail out with\n-EOVERFLOW via fsuidgid_has_mapping() precisely so that an object cannot\nbe created with an owner the filesystem cannot represent.  An O_TMPFILE\nis no exception: it is created I_LINKABLE and linkat(2) can splice it\ninto the namespace afterwards, so the same guarantee must hold.\n\nAdd the missing fsuidgid_has_mapping() check to vfs_tmpfile().  On a\nnon-idmapped mount the caller's fs{u,g}id always map in the superblock's\nuser namespace, so this is a no-op there and only takes effect on an\nidmapped mount that does not map the caller.  It applies to every\nfilesystem that sets FS_ALLOW_IDMAP and implements ->tmpfile() (tmpfs,\next4, btrfs, xfs, f2fs, ...), and to overlayfs, whose upper-layer\ntmpfile creation funnels through vfs_tmpfile() via backing_tmpfile_open()."}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/namei.c"],"versions":[{"version":"8e5389132ab429604c1a2459b52f0c849a71cc61","lessThan":"bac8fb0d60254846f3b56957435dcd870ae12948","status":"affected","versionType":"git"},{"version":"8e5389132ab429604c1a2459b52f0c849a71cc61","lessThan":"503d0568a525b168d9aa5ca046ec72fc5477df84","status":"affected","versionType":"git"},{"version":"8e5389132ab429604c1a2459b52f0c849a71cc61","lessThan":"a2038514e69371eb493083a6a897ed20fcbb8acb","status":"affected","versionType":"git"},{"version":"8e5389132ab429604c1a2459b52f0c849a71cc61","lessThan":"47e434da476b5a8bcd1e6e52ab03c5ee7764ee78","status":"affected","versionType":"git"},{"version":"8e5389132ab429604c1a2459b52f0c849a71cc61","lessThan":"539dce1144651f7976fa418e618b0b574bf15eeb","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/namei.c"],"versions":[{"version":"5.13","status":"affected"},{"version":"0","lessThan":"5.13","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":"5.13","versionEndExcluding":"6.6.145"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.12.97"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.18.40"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"7.1.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"7.2"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/bac8fb0d60254846f3b56957435dcd870ae12948"},{"url":"https://git.kernel.org/stable/c/503d0568a525b168d9aa5ca046ec72fc5477df84"},{"url":"https://git.kernel.org/stable/c/a2038514e69371eb493083a6a897ed20fcbb8acb"},{"url":"https://git.kernel.org/stable/c/47e434da476b5a8bcd1e6e52ab03c5ee7764ee78"},{"url":"https://git.kernel.org/stable/c/539dce1144651f7976fa418e618b0b574bf15eeb"}],"title":"fs: refuse O_TMPFILE creation with an unmapped fsuid or fsgid","x_generator":{"engine":"bippy-1.2.0"}}}}