CVE-2026-98899: Linux kernel · netfilter: ipset: mark the rcu locked areas properly
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 7.8 High · fixed in eee5172741b2c0e73210020732043e5d589295d3 : patch Linux kernel soon.
Data as of 26 Oct 2026, 13:07 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in eee5172741b2c0e73210020732043e5d589295d3, ecb48c6b9edc78de8dd456c365727ae14b88c1ee, ca9fab1ca15534cef1630e81a479e94b3bbcdb6a +6
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 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
|
| LinuxLinux | Affected
| Fixed in– |
AI-suggested
A fix is available and has been applied in Linux kernel versions 5.5, 5.6, and related commits. Users and administrators should upgrade to these fixed versions or later to remediate the vulnerability. Since this is a kernel-level issue, applying the official kernel updates from the Linux distribution or kernel maintainers is the recommended mitigation.
Description
CVE-2026-98899 is a high-severity vulnerability in the Linux kernel's netfilter ipset component. It involves improper marking of RCU (Read-Copy-Update) locked areas, which could lead to incorrect locking behavior. The issue was resolved by properly marking RCU locked areas and adjusting locking mechanisms during reference count increments and garbage collection. This vulnerability affects multiple Linux kernel versions prior to 5.5, 5.6, and exactly version 5.6.
References
- git.kernel.org/stable/c/67bd3d2350d17c2f4fb158c3f917c10b15ecbc94 (opens in a new tab)
- git.kernel.org/stable/c/892399abd1a005a455d5b74d86d82b9773405f2b (opens in a new tab)
- git.kernel.org/stable/c/eee5172741b2c0e73210020732043e5d589295d3 (opens in a new tab)
- git.kernel.org/stable/c/ecb48c6b9edc78de8dd456c365727ae14b88c1ee (opens in a new tab)
- git.kernel.org/stable/c/0c46c9ce24130657ec7460c27fba5d445f5abd06 (opens in a new tab)
- git.kernel.org/stable/c/ca9fab1ca15534cef1630e81a479e94b3bbcdb6a (opens in a new tab)
- git.kernel.org/stable/c/5d0c22e73656d050daffad10a2ba8765ce8441c8 (opens in a new tab)