CVE-2025-68358: Linux kernel · btrfs: fix racy bitfield write in btrfs_clear_space_info_full()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 6.8.0-1057.60~22.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.8.0-1057.60~22.04.1, 6.8.0-1059.65~22.04.1, 6.8.0-1060.63~22.04.1 +41
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 24 Dec 2025
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 |
|---|---|---|
Ubuntu 25.10linuxpkg:deb/ubuntu/linux@6.17.0-19.19?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws@6.17.0-1009.9?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure@6.17.0-1010.10?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde@6.17.0-1017.17?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-gcppkg:deb/ubuntu/linux-gcp@6.17.0-1009.9?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle@6.17.0-1009.9?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
An official patch is available that replaces the vulnerable bitfield members with boolean variables to ensure safe concurrent access. Users should apply the vendor-provided updates to affected Linux kernel versions. No additional mitigation is indicated by the vendor advisory.
Description
A race condition vulnerability in the Linux kernel's btrfs filesystem was fixed, specifically in the function btrfs_clear_space_info_full(). The issue arises from non-atomic read-modify-write operations on bitfields that are not properly synchronized with locks, leading to a broken invariant in space_info->flush state. This can cause blocking conditions in space allocation, resulting in denial of service. The fix replaces the bitfield members with boolean variables to avoid unsafe concurrent writes.
References
- ubuntu.com/security/CVE-2025-68358 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-68358 (opens in a new tab)
- git.kernel.org/stable/c/38e818718c5e04961eea0fa8feff3f100ce40408 (opens in a new tab)
- git.kernel.org/stable/c/6f442808a86eef847ee10afa9e6459494ed85bb3 (opens in a new tab)
- git.kernel.org/stable/c/742b90eaf394f0018352c0e10dc89763b2dd5267 (opens in a new tab)
- ubuntu.com/security/notices/USN-8094-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8094-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8094-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8094-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8094-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-8152-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8278-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8289-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8296-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8296-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8289-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8278-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8393-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8440-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8499-1 (opens in a new tab)