In the Linux kernel, the following vulnerability has been resolved: fuse: re-lock request before returning from fuse_ref_folio() fuse_ref_folio()… (CVE-2026-64266)
Source GCVE Database
Not known to be exploited : update affected systems when convenient.
Data as of 10/24/2026, 17:08:26 UTC
No CVSS score from NVD or the CNA
- Exploitation
Not in CISA KEV, no exploitation reported
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
What to do
AI-suggested
A fix has been implemented in the Linux kernel to re-lock the request before returning from fuse_ref_folio(). Users should apply the official kernel updates that include this patch once available.
Description
In the Linux kernel, the following vulnerability has been resolved: fuse: re-lock request before returning from fuse_ref_folio() fuse_ref_folio() unlocks the request but does not re-lock it before returning. fuse_chan_abort() can end the request and the async end callback (eg fuse_writepage_free()) can free the args while the subsequent copy chain logic after fuse_ref_folio() accesses them, leading to use-after-free issues. Fix this by locking the request in fuse_ref_folio() before returning.
Impact
This vulnerability could lead to use-after-free conditions within the kernel, potentially causing system instability or crashes. The information does not specify any known exploitation in the wild or direct privilege escalation, but use-after-free bugs in kernel code can be serious if exploited.
Summary
The vulnerability in the Linux kernel's FUSE implementation involves fuse_ref_folio() unlocking a request without re-locking it before returning. This allowed fuse_chan_abort() to end the request and trigger asynchronous callbacks that could free memory still in use by subsequent copy chain logic, resulting in use-after-free conditions. The fix involved modifying fuse_ref_folio() to re-lock the request before returning, preventing premature freeing of resources.
References
- nvd.nist.gov/vuln/detail/CVE-2026-64266 (opens in a new tab)
- git.kernel.org/stable/c/0e4a5a000123d81234e27a2f8187688cf608f755 (opens in a new tab)
- git.kernel.org/stable/c/1ca605cfa59377f0143fb35b5b01360f37d1b7c4 (opens in a new tab)
- git.kernel.org/stable/c/1f9156714592356b4fda57beac7eab9c2a462dd3 (opens in a new tab)
- git.kernel.org/stable/c/5630da218a45ba80f0aba0846cbe8aa655da122b (opens in a new tab)
- git.kernel.org/stable/c/65a1c2551f7e16085acbb54aedde1feaa559ba7a (opens in a new tab)
- git.kernel.org/stable/c/b5befa80fdbe287a98480effed9564712924add5 (opens in a new tab)
- git.kernel.org/stable/c/be353caffa8640f5e25fb3714ce8b0cef5e410e5 (opens in a new tab)
- git.kernel.org/stable/c/e6aa539720c3d8def69683ed0c07cf9faea4e8be (opens in a new tab)