{"id":"CVE-2026-93235","summary":"f2fs: fix to zero post-EOF data when extending file size","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to zero post-EOF data when extending file size\n\ngeneric/794  4s ... - output mismatch (see /share/git/fstests/results//generic/794.out.bad)\n    --- tests/generic/794.out   2026-06-12 08:46:32.766426241 +0800\n    +++ /share/git/fstests/results//generic/794.out.bad 2026-07-05 18:32:55.000000000 +0800\n    @@ -1,4 +1,16 @@\n     QA output created by 794\n     append_write\n    +FAIL: non-zero data in gap [4080,4096) after shutdown+remount\n    +000000 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a  \u003eZZZZZZZZZZZZZZZZ\u003c\n    +*\n    +001000\n     truncate_up\n    ...\n    (Run 'diff -u /share/git/fstests/tests/generic/794.out /share/git/fstests/results//generic/794.out.bad'  to see the entire diff)\nRan: generic/794\nFailures: generic/794\nFailed 1 of 1 tests\n\nSteps of generic/794:\n1. write 4096 bytes to file w/ 0x5a\n2. use fiemap to get PBA of first block in file\n3. truncate file to 4080\n4. umount; write 4096 bytes to file w/ 0x5a directly via PBA; mount\n5. extend filesize via\n   a) append 4096 from offset 4096, or\n   b) truncate 8192, or\n   c) fallocate 4096 from offset 4096\n6. verify the gap is zeroed in memory [4080,4096)\n7. sync range 4096 from offset 4096; shutdown -f (flush meta before shutdown)\n8. umount; mount; verify [4080,4096) is zeroed or not.\n\nWhen extending file size (e.g. via truncate, fallocate, or write) across an\nunaligned EOF boundary, we need to ensure that post-EOF data in the partial\npage is zeroed out in pagecache and marked dirty, then writeback the cache to\npersist zeroed data before committing inode w/ updated i_size.\n\nThis help to prevent stale disk data beyond the previous EOF from being exposed\nafter remounting or crash recovery.\n\nSince f2fs is a LFS filesystem, we only support direct write via PBA in pinfile,\nand pinfile has section-aligned filesize, so in Android, there should no problem,\nbut for other usage in different environment, let's fix this w/ fsync_mode=strict\nmount option.","modified":"2026-09-26T03:48:38.701065674Z","published":"2026-09-24T15:33:33.241Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93235.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/32c7f11a24268ba8d3bb50ea7f54d33f698cd253"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5eced87b7d19dbc76ebdddaf322046f9ac582fcb"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6882d458d2e403f6ba7b45542dd31a6b7531eb2e"},{"type":"WEB","url":"https://git.kernel.org/stable/c/91ec55ddc097ccddd25ffb95a3d079b2ef362372"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c42608c09b6b5d5967bf211c255914c068c2cde1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93235.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-93235"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"fbfa2cc58d5363f780f4f2ad0243a47185c2bb2a"},{"fixed":"6882d458d2e403f6ba7b45542dd31a6b7531eb2e"},{"fixed":"32c7f11a24268ba8d3bb50ea7f54d33f698cd253"},{"fixed":"91ec55ddc097ccddd25ffb95a3d079b2ef362372"},{"fixed":"c42608c09b6b5d5967bf211c255914c068c2cde1"},{"fixed":"5eced87b7d19dbc76ebdddaf322046f9ac582fcb"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-93235.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.8.0"},{"fixed":"6.6.157"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.110"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.51"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.5"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-93235.json"}}],"schema_version":"1.9.0"}