CVE-2026-98538: Linux kernel · writeback: bound cleanup_offline_cgwb() rescans by rotating scanned inodes
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in f6988c90671e83db79df1b7b9d6fdb0e5947fd84 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 14:05 UTC
Rated Medium by Threat Radar's AI analysis · CVSS not yet scored by NVD
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 11% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in f6988c90671e83db79df1b7b9d6fdb0e5947fd84, dd4b92067238771b604b59fdda8efed6d70ee823, c96b4d1628868e1195da1a896f79e06f350a3187 +3
Exploitation evidence
Disclosed: evidence found.
CVE published 18 Oct 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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AI-suggested
A fix for this vulnerability is available and has been applied in multiple Linux kernel commits. Users running affected versions, specifically Linux kernel 5.14, should update to a fixed kernel version containing the referenced commits. No additional mitigation actions are indicated by the vendor advisory.
Description
CVE-2026-98538 is a Linux kernel vulnerability affecting version 5.14 where the cleanup_offline_cgwb() function rescans inodes inefficiently, causing a quadratic time complexity in draining writeback inodes. This can lead to soft lockups with CPUs stuck for extended periods when many inodes are attached to a dying writeback control group. The issue is fixed by reordering inode scans to achieve linear time complexity.
References
- git.kernel.org/stable/c/2d1da58c79b66646721a644c6eb4dd1f9c5c9327 (opens in a new tab)
- git.kernel.org/stable/c/c96b4d1628868e1195da1a896f79e06f350a3187 (opens in a new tab)
- git.kernel.org/stable/c/624dd0931162523d70f9db8c120b5ec6429a9b97 (opens in a new tab)
- git.kernel.org/stable/c/dd4b92067238771b604b59fdda8efed6d70ee823 (opens in a new tab)
- git.kernel.org/stable/c/9dac137bf77e0683778fb34c86e730c6129e8cb6 (opens in a new tab)
- git.kernel.org/stable/c/f6988c90671e83db79df1b7b9d6fdb0e5947fd84 (opens in a new tab)