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CVE-2026-31694NVD
Vulnerability Summary
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.
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.
CVSS v3.1 Base Metrics — Score 7.8 (HIGH)
Attack VectorLocal
Attack ComplexityLow
Privileges RequiredLow
User InteractionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
Affected & Patched Versions
- Linux Linux Kernel >= 4.20 and < 6.6.136
- Linux Linux Kernel >= 6.7 and < 6.12.84
- Linux Linux Kernel >= 6.13 and < 6.18.25
- Linux Linux Kernel >= 6.19 and < 7.0.2
- Linux Linux Kernel
- Linux Linux Kernel 6.6.136
- Linux Linux Kernel 6.12.84
- Linux Linux Kernel 6.18.25
- Linux Linux Kernel 7.0.2