CVE-2026-90110: Linux kernel · inetpeer: randomize RB-tree node comparison using SipHash
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 9.4 Critical.
Data as of 26 Oct 2026, 12:55 UTC
- EPSS
- 0.6% chance of exploitation in 30 days – higher than 48% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:LExploitation evidence
Disclosed: evidence found.
CVE published 17 Sep 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
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther 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
A fix is available that randomizes the RB-tree node comparison logic using SipHash with a secret key, breaking the deterministic eviction mechanism. Users should apply the official Linux kernel updates that include this patch. Patch status is confirmed by the resolution of CVE-2026-90110. Check vendor advisories for the specific patched kernel versions.
Description
A vulnerability in the Linux kernel's inetpeer rate limiting system allowed off-path attackers to bypass IP-keyed ICMP rate limits and infer open UDP ports by exploiting deterministic Red-Black tree node comparisons. The flaw was due to predictable tree traversal paths, enabling selective eviction and reset of rate-limiting tokens. The issue was mitigated by randomizing the RB-tree node comparison using SipHash with a secret key, making the tree layout unpredictable to attackers.
References
- nvd.nist.gov/vuln/detail/CVE-2026-90110 (opens in a new tab)
- git.kernel.org/stable/c/199fcf285e498111e029137d088949bc6c26d578 (opens in a new tab)
- git.kernel.org/stable/c/2ee66e9487172fcd189bc52a767c30dad7141c09 (opens in a new tab)
- git.kernel.org/stable/c/5f127e3cc9647a8a70db12c65dbd0de473545380 (opens in a new tab)
- git.kernel.org/stable/c/7109bb63667a53e4542ad845476f97d0c8b28a61 (opens in a new tab)
- git.kernel.org/stable/c/857681f6835d5b0a7bc4a34a026baeaaf5215623 (opens in a new tab)
- git.kernel.org/stable/c/b20e98f0bb668a59abaf7bcf85d75c073e90d352 (opens in a new tab)
- ubuntu.com/security/CVE-2026-90110 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-90110 (opens in a new tab)
- git.kernel.org/linus/2ee66e9487172fcd189bc52a767c30dad7141c09 (opens in a new tab)