erofs: fix the out-of-bounds nameoff handling for trailing dirents

Summary

In the Linux kernel, the following vulnerability has been resolved: erofs: fix the out-of-bounds nameoff handling for trailing dirents Currently we already have boundary-checks for nameoffs, but the trailing dirents are special since the namelens are calculated with strnlen() with unchecked nameoffs. If a crafted EROFS has a trailing dirent with nameoff >= maxsize, maxsize - nameoff can underflow, causing strnlen() to read past the directory block. nameoff0 should also be verified to be a multiple of `sizeof(struct erofs_dirent)` as well [1]. [1] https://sashiko.dev/#/patchset/20260416063511.3173774-1-hsiangkao%40linux.alibaba.com

Timeline

1. May 27, 2026, 12:58 PM UTCCVE published
2. Oct 16, 2026, 3:19 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: partial

3. Oct 19, 2026, 7:26 PM UTCRecord last updated

Affected versions

• Linux Linux

  From 3aa8ec716e52c02360457fa018296629b4d0becf · fixed in a8ee527807f7d97e55ce2ef2906f7f34975eb1c7; From 3aa8ec716e52c02360457fa018296629b4d0becf · fixed in aa16dca1b062355181ef215229eeac249d7c0d61; From 3aa8ec716e52c02360457fa018296629b4d0becf · fixed in 80a23c6d1aba35be8746d74ac14e6ba5ae46da21; From 3aa8ec716e52c02360457fa018296629b4d0becf · fixed in 222055e6b4063abd2d9e13c3d49bbd1724c50789; From 3aa8ec716e52c02360457fa018296629b4d0becf · fixed in 48b27a955d22391c7f30169fa7b6b2e1977f1ce4; From 3aa8ec716e52c02360457fa018296629b4d0becf · fixed in 8ebb951a284b7446e025afc7dc5e9516ef9a7214; From 3aa8ec716e52c02360457fa018296629b4d0becf · fixed in 1d55445226c75ddd4e78b09b3e7d99109b28c366; From 3aa8ec716e52c02360457fa018296629b4d0becf · fixed in d18a3b5d337fa412a38e776e6b4b857a58836575

• Linux Linux

  4.19

• KernelLinux

  From 4.19.0 · fixed in 5.10.259; From 5.11.0 · fixed in 5.15.210; From 5.16.0 · fixed in 6.1.175; From 6.2.0 · fixed in 6.6.140; From 6.7.0 · fixed in 6.12.86; From 6.13.0 · fixed in 6.18.27; From 6.19.0 · fixed in 7.0.4

References 8