CVE-2026-31694fuse: reject oversized dirents in page cache
Updated under an hour ago ()
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It affects Linux and 2 other products. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Modified
- Record last updated
- Oct 15, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | 27992ef80770d61a57f6c3a551735b08cefdffa3 builds before 7de93abfaae1b2dc94da8a07a36421bd073f1d8f; 27992ef80770d61a57f6c3a551735b08cefdffa3 builds before 474ce83c96a55f2eeb14dee2be375eeadfdacdf5; 27992ef80770d61a57f6c3a551735b08cefdffa3 builds before 51a8de6c50bf947c8f534cd73da4c8f0a13e7bed | CNA record |
Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem siemens:simatic_s7_1500_tm_mfp_gnu_linux_subsystem (from the name) | all versions | CISA ADP |
linux linux_kernel linux:linux_kernel | from 4.20 before 6.6.136; from 6.7 before 6.12.84; from 6.13 before 6.18.25; from 6.19 before 7.0.2; 7.1; 7.1 | NVD |
References
- https://git.kernel.org/stable/c/7de93abfaae1b2dc94da8a07a36421bd073f1d8fpatch
- https://git.kernel.org/stable/c/474ce83c96a55f2eeb14dee2be375eeadfdacdf5patch
- https://git.kernel.org/stable/c/51a8de6c50bf947c8f534cd73da4c8f0a13e7bedpatch
- https://cert-portal.siemens.com/productcert/html/ssa-784472.html
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.