CVE-2026-31694: fuse: reject oversized dirents in page cache
Vulnerability summary
CVE-2026-31694 is a high (CVSS 7.8) vulnerability in linux. EPSS estimates a 0.28% chance of exploitation in the next 30 days, higher than 21% of scored vulnerabilities.
Not severe (CVSS 7.8, local access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 135 · Related 133Showing 100 of 136.
Timeline
- 01-05-2026PublishedVulnerability first disclosed.
- 15-10-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
6 scores · 5 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- OSV · ChainguardEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- NVDNIST7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.28%
Chance of exploitation in the next 30 days
Percentile
21%
Versus all other CVEs
30-day change
Increase +0.11 pp
From 0.17% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeNo weakness data has been published for this record.
Affected systems
Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu154 products
- linuxAll versions (No fix recorded) | < 5.15.0-186.196 | < 6.8.0-136.136 | < 7.0.0-27.27
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 5.15.0-1112.119 | < 6.8.0-1061.64 | < 7.0.0-1008.8
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Chainguard6 products
- linux-aws-6.18< 6.18.31-r0
- linux-azure-6.18< 6.18.24-r1 | < 6.18.31-r0
- linux-gcp-6.18< 6.18.31-r0
- linux-qemu-6.18< 6.18.24-r3
- linux-qemu-rc< 7.1_rc3-r0
Linux2 products
- linux≥ 27992ef80770d61a57f6c3a551735b08cefdffa3, < 7de93abfaae1b2dc94da8a07a36421bd073f1d8f | ≥ 27992ef80770d61a57f6c3a551735b08cefdffa3, < 474ce83c96a55f2eeb14dee2be375eeadfdacdf5 | ≥ 27992ef80770d61a57f6c3a551735b08cefdffa3, < 51a8de6c50bf947c8f534cd73da4c8f0a13e7bed | 6.15
- linux_kernel≥ 4.20, < 6.6.136 | ≥ 6.7, < 6.12.84 | ≥ 6.13, < 6.18.25 | ≥ 6.15, < 6.18.25 | ≥ 6.19, < 7.0.2 | 7.1:rc1 | 7.1:rc2
Debian1 product
- linux< 7.0.3-1
Siemens1 product
5 vendors · 164 products
References
43 linksShow all 43 references
- cert-portal.siemens.com/productcert/html/ssa-784472.htmlThird Party Advisory