5.5

CVE-2026-64263: fuse-uring: fix moving cancelled entry to ent_in_userspace list

Analyzed
AliasesUBUNTU-CVE-2026-64263DEBIAN-CVE-2026-64263CGA-6789-6hp3-mh7p
Published 25-07-2026Last modified 17-08-2026

Vulnerability summary

CVE-2026-64263 is a medium (CVSS 5.5) vulnerability in linux. EPSS estimates a 0.16% chance of exploitation in the next 30 days, higher than 5.2% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.5/10
010
Medium · v3.1 (NVD)
EPSS score
0.16%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 12 · Related 13
OPENSUSE-SU-2026:11476-1USN-8726-1USN-8726-2USN-8726-3USN-8726-4USN-8727-1

Timeline

  1. 25-07-2026
    PublishedVulnerability first disclosed.
  2. 17-08-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: fuse-uring: fix moving cancelled entry to ent_in_userspace list fuse_uring_cancel() moves entries that are available (these have no reqs attached) to the ent_in_userspace list. ent_list_request_expired() checks the first entry on ent_in_userspace and dereferences ent->fuse_req unconditionally, which will crash on a cancelled entry that was moved to this list. Fix this by freeing the entry and dropping queue_refs directly in fuse_uring_cancel(). This is safe because cancel is the cancel handler itself - after io_uring_cmd_done(), no more cancels will be dispatched for this command, and teardown serializes with cancel via queue->lock. Since cancel now decrements queue_refs, fuse_uring_abort() must no longer gate fuse_uring_abort_end_requests() on queue_refs > 0, as cancelled entries may have already dropped queue_refs while requests are still queued. Remove the gate so abort always flushes requests and stops queues.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.16%

Chance of exploitation in the next 30 days

Percentile

5%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.16% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu119 products
  • linux< 7.0.0-31.31
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws< 7.0.0-1012.12
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Chainguard2 products
  • linux-gcp-6.18< 6.18.44-r0
  • linux-gcp-6.18-bootc< 6.18.44-r0
Linux2 products
  • linux≥ 4fea593e625cd50d4d11be227007849b12f17bfb, < 50f3e03db823cabc41fe35c27d77c2bdb112baad | ≥ 4fea593e625cd50d4d11be227007849b12f17bfb, < e8afc85acdf329361b2d8df2ad9b52364686235f | ≥ 4fea593e625cd50d4d11be227007849b12f17bfb, < 198f45eeb9f78b2a2d6d8be95e4e43468eb2c6bc | 6.16
  • linux_kernel≥ 6.16, < 6.18.39 | ≥ 6.19, < 7.1.4
Debian1 product
  • linux< 7.1.4-1

4 vendors · 124 products

References

18 links
Show all 18 references