CVE-2026-31694 | fuse: reject oversized dirents in page cache

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.

Published: 2026-05-01 Last update: 2026-06-17 Assigner: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Conclusion & alert: CVE-2026-31694 is rated Low Risk (32.3/100): CVSS High severity, with low exploitation likelihood (EPSS 0.13%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-31694

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.02% 0.13% +0.11%
2 2026-05-02 0.02%

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-31694

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
1.8 5.9 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Weakness enumeration for CVE-2026-31694

GitHub Security Advisory for CVE-2026-31694

GHSA-8fxx-fj7q-42m6 · Severity: high — In the Linux kernel, the following vulnerability has been resolved: fuse: reject oversized...

OS Trackers for CVE-2026-31694

vendor priority summary link
debian not yet assigned CVE-2026-31694 not yet assigned priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 3, open 2. https://security-tracker.debian.org/tracker/CVE-2026-31694
redhat high https://access.redhat.com/security/cve/CVE-2026-31694
suse high CVE-2026-31694 severity important: SUSE including 14 source package names (cluster-md-kmp-default, dlm-kmp-default, …), 37 product×package rows across 7 product lines (SUSE Linux Enterprise Live Patching 12 SP5, SUSE Linux Enterprise Micro 5.0, … (7 product lines)): Known Not Affected 37. https://www.suse.com/security/cve/CVE-2026-31694/
ubuntu medium CVE-2026-31694 medium priority: Ubuntu including 161 source packages (linux, linux-allwinner-5.19, …), 1449 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): DNE 1048, ignored 169, needed 121, released 83, not-affected 23, needs-triage 4, pending 1. https://ubuntu.com/security/CVE-2026-31694

Affected software / configurations for CVE-2026-31694

Vendor Product Version Raw CPE
linux linux_kernel >= 4.20, < 6.6.136 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.7, < 6.12.84 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.13, < 6.18.25 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.19, < 7.0.2 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel 7.1 cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*
linux linux_kernel 7.1 cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*

References for CVE-2026-31694

cvelogic Threat Intelligence