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CVE-2026-64296

exfat: bound uniname advance in exfat_find_dir_entry()

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, and 2 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: total

Summary

In the Linux kernel, the following vulnerability has been resolved: exfat: bound uniname advance in exfat_find_dir_entry() In exfat_find_dir_entry(), each TYPE_EXTEND (file name) entry advances the output pointer by a fixed amount while the loop guard only tracks the accumulated name length: if (++order == 2) uniname = p_uniname->name; else uniname += EXFAT_FILE_NAME_LEN; len = exfat_extract_uni_name(ep, entry_uniname); name_len += len; unichar = *(uniname+len); *(uniname+len) = 0x0; uniname grows by EXFAT_FILE_NAME_LEN (15) per name entry, but name_len grows only by the actual extracted length, which is shorter when a name fragment contains an early NUL. The only guard is `name_len >= MAX_NAME_LENGTH`, so a crafted directory with many short name fragments lets uniname run far past the p_uniname->name[MAX_NAME_LENGTH + 3] buffer while name_len stays small, causing an out-of-bounds read and write at *(uniname+len). The sibling extractor exfat_get_uniname_from_ext_entry() already stops on a short fragment (the lockstep `len != EXFAT_FILE_NAME_LEN` guard added in commit d42334578eba ("exfat: check if filename entries exceeds max filename length")); exfat_find_dir_entry() never got the equivalent. Track the per-entry write offset as a count and reject a fragment once the offset, or the offset plus the extracted length, would exceed MAX_NAME_LENGTH, before forming the output pointer.

Timeline

  1. CVE published
  2. CISA SSVC assessment

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

  3. Record last updated

Affected versions

  • Linux Linux

    From ca06197382bde0a3bc20215595d1c9ce20c6e341 · fixed in 72a2589d82eb001c94b74bcfe6f9a599bd9bef60; From ca06197382bde0a3bc20215595d1c9ce20c6e341 · fixed in fae76a94b35ee8c0e2eb6f64caca01d75c6d34e4; From ca06197382bde0a3bc20215595d1c9ce20c6e341 · fixed in cf85180b8a015029ee147694eaf4e0b3537e9432; From ca06197382bde0a3bc20215595d1c9ce20c6e341 · fixed in ce4736c1e6c4cfbf1ac409a8c328a0b69546c9a0; From ca06197382bde0a3bc20215595d1c9ce20c6e341 · fixed in 727bf7783a2936ffd55c628dddfd69343e511dcf; From ca06197382bde0a3bc20215595d1c9ce20c6e341 · fixed in 33c0b96d7e1672be1de0053786637ea46fb81507; From ca06197382bde0a3bc20215595d1c9ce20c6e341 · fixed in c8e041c68c0bbb73aa62371ee63947bb6949d8b2; From ca06197382bde0a3bc20215595d1c9ce20c6e341 · fixed in 3a1230e7b043c62737b05a3e9275ca83a43ad20a

  • Linux Linux

    5.7

  • KernelLinux

    From 5.7.0 · fixed in 5.10.261; From 5.11.0 · fixed in 5.15.212; From 5.16.0 · fixed in 6.1.178; From 6.2.0 · fixed in 6.6.145; From 6.7.0 · fixed in 6.12.96; From 6.13.0 · fixed in 6.18.39; From 6.19.0 · fixed in 7.1.4

References 8

git.kernel.org