fuse: reject oversized dirents in page cache
Summary
| CVE | CVE-2026-31694 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-05-01 14:16:19 UTC |
| Updated | 2026-05-03 07:16:16 UTC |
| Description | In the Linux kernel, the following vulnerability has been resolved: fuse: reject oversized dirents in page cache fuse_add_dirent_to_cache() computes a serialized dirent size from the server-controlled namelen field and copies the dirent into a single page-cache page. The existing logic only checks whether the dirent fits in the remaining space of the current page and advances to a fresh page if not. It never checks whether the dirent itself exceeds PAGE_SIZE. As a result, a malicious FUSE server can return a dirent with namelen=4095, producing a serialized record size of 4120 bytes. On 4 KiB page systems this causes memcpy() to overflow the cache page by 24 bytes into the following kernel page. Reject dirents that cannot fit in a single page before copying them into the readdir cache. |
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: 0.000180000 probability, percentile 0.048520000 (date 2026-05-02)
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | Secondary | 7.8 | HIGH | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| 3.1 | CNA | DECLARED | 7.8 | HIGH | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
CVSS v3.1 Breakdown
Attack Vector
LocalAttack Complexity
LowPrivileges Required
LowUser Interaction
NoneScope
UnchangedConfidentiality
HighIntegrity
HighAvailability
HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected 69e34551152a286f827d54dcb5700da6aeaac1fb d23ad78bfd205eac26766e38ba7d79f279131098 git | Not specified |
| CNA | Linux | Linux | affected 69e34551152a286f827d54dcb5700da6aeaac1fb 45c05af36311624c1148123caeb011312495d86b git | Not specified |
| CNA | Linux | Linux | affected 69e34551152a286f827d54dcb5700da6aeaac1fb 7de93abfaae1b2dc94da8a07a36421bd073f1d8f git | Not specified |
| CNA | Linux | Linux | affected 69e34551152a286f827d54dcb5700da6aeaac1fb 474ce83c96a55f2eeb14dee2be375eeadfdacdf5 git | Not specified |
| CNA | Linux | Linux | affected 69e34551152a286f827d54dcb5700da6aeaac1fb 51a8de6c50bf947c8f534cd73da4c8f0a13e7bed git | Not specified |
| CNA | Linux | Linux | affected 4.20 | Not specified |
| CNA | Linux | Linux | unaffected 4.20 semver | Not specified |
| CNA | Linux | Linux | unaffected 6.6.136 6.6.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.12.84 6.12.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.18.25 6.18.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.0.2 7.0.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.1-rc1 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/45c05af36311624c1148123caeb011312495d86b | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/51a8de6c50bf947c8f534cd73da4c8f0a13e7bed | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/7de93abfaae1b2dc94da8a07a36421bd073f1d8f | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/474ce83c96a55f2eeb14dee2be375eeadfdacdf5 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/d23ad78bfd205eac26766e38ba7d79f279131098 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.