CVE-2026-64600: Linux kernel · Race Condition
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 7.8 High · fixed in e705d81a7193dd19e69b8e2bad4696d78a4ea075 : patch Linux kernel soon.
Data as of 26 Oct 2026, 10:24 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 40% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in e705d81a7193dd19e69b8e2bad4696d78a4ea075, dc11be133efca5fe3a2fb02b016dee825cc12f18, b8c9aa832b52680ee40d6cab0efb081f9a69df05 +4
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 23 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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Description
In the Linux kernel, the following vulnerability has been resolved: xfs: resample the data fork mapping after cycling ILOCK xfs_reflink_fill_{cow_hole,delalloc} are both presented with an inode, a data fork mapping, and a cow fork mapping. Unfortunately, these two helpers cycle the ILOCK to grab a transaction, which means that the mappings are stale as soon as we reacquire the ILOCK. Currently we refresh the cow fork mapping by re-calling xfs_find_trim_cow_extent, but we don't refresh the data fork mapping beforehand, which means that the xfs_bmap_trim_cow in that function queries the refcount btree about the wrong physical blocks and returns an inaccurate value in *shared. If *shared is now false, the directio write proceeds with a stale data fork mapping. Fix this by querying the data fork mapping if the sequence counter changes across the ILOCK cycle.
References
- git.kernel.org/stable/c/dc11be133efca5fe3a2fb02b016dee825cc12f18 (opens in a new tab)
- git.kernel.org/stable/c/b8c9aa832b52680ee40d6cab0efb081f9a69df05 (opens in a new tab)
- git.kernel.org/stable/c/50f0012da1040f69a4e788cd9aed587c9a04983f (opens in a new tab)
- git.kernel.org/stable/c/e705d81a7193dd19e69b8e2bad4696d78a4ea075 (opens in a new tab)
- git.kernel.org/stable/c/206c09b04dc5469c7ff14d8aceff2d47c88078d9 (opens in a new tab)
- git.kernel.org/stable/c/44f891bc088958399eec27f7604928694aa35581 (opens in a new tab)
- git.kernel.org/stable/c/2f4acd0fcd862e22eab45690ec2c08c80b6ef2e7 (opens in a new tab)
- cdn2.qualys.com/advisory/2026/07/22/RefluXFS.txt (opens in a new tab)
- openwall.com/lists/oss-security/2026/07/22/14 (opens in a new tab)
- openwall.com/lists/oss-security/2026/07/22/18 (opens in a new tab)
- openwall.com/lists/oss-security/2026/07/22/19 (opens in a new tab)
- openwall.com/lists/oss-security/2026/07/31/3 (opens in a new tab)
- openwall.com/lists/oss-security/2026/08/03/4 (opens in a new tab)
- openwall.com/lists/oss-security/2026/08/03/8 (opens in a new tab)