exfat: bound uniname advance in exfat_find_dir_entry()

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-64296
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-25 10:17:10 UTC
Updated2026-08-12 14:56:25 UTC
DescriptionIn 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.

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.001640000 probability, percentile 0.060520000 (date 2026-08-03)

Problem Types: NVD-CWE-noinfo

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected ca06197382bde0a3bc20215595d1c9ce20c6e341 72a2589d82eb001c94b74bcfe6f9a599bd9bef60 git Not specified
CNA Linux Linux affected ca06197382bde0a3bc20215595d1c9ce20c6e341 fae76a94b35ee8c0e2eb6f64caca01d75c6d34e4 git Not specified
CNA Linux Linux affected ca06197382bde0a3bc20215595d1c9ce20c6e341 cf85180b8a015029ee147694eaf4e0b3537e9432 git Not specified
CNA Linux Linux affected ca06197382bde0a3bc20215595d1c9ce20c6e341 ce4736c1e6c4cfbf1ac409a8c328a0b69546c9a0 git Not specified
CNA Linux Linux affected ca06197382bde0a3bc20215595d1c9ce20c6e341 727bf7783a2936ffd55c628dddfd69343e511dcf git Not specified
CNA Linux Linux affected ca06197382bde0a3bc20215595d1c9ce20c6e341 33c0b96d7e1672be1de0053786637ea46fb81507 git Not specified
CNA Linux Linux affected ca06197382bde0a3bc20215595d1c9ce20c6e341 c8e041c68c0bbb73aa62371ee63947bb6949d8b2 git Not specified
CNA Linux Linux affected ca06197382bde0a3bc20215595d1c9ce20c6e341 3a1230e7b043c62737b05a3e9275ca83a43ad20a git Not specified
CNA Linux Linux affected 5.7 Not specified
CNA Linux Linux unaffected 5.7 semver Not specified
CNA Linux Linux unaffected 5.10.261 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.212 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.178 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.145 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.96 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.39 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.4 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/fae76a94b35ee8c0e2eb6f64caca01d75c6d34e4 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/3a1230e7b043c62737b05a3e9275ca83a43ad20a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/727bf7783a2936ffd55c628dddfd69343e511dcf 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/33c0b96d7e1672be1de0053786637ea46fb81507 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/72a2589d82eb001c94b74bcfe6f9a599bd9bef60 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/ce4736c1e6c4cfbf1ac409a8c328a0b69546c9a0 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/cf85180b8a015029ee147694eaf4e0b3537e9432 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/c8e041c68c0bbb73aa62371ee63947bb6949d8b2 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
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