Kernel networking bug affects widespread Linux deployments, enabling off‑path bypass of rate limits and UDP reconnaissance — requires org‑wide attention and patching.
CVE-2026-90110
Linux kernel inetpeer RB-tree predictability allows off‑path rate‑limit bypass & UDP port inference
do firstUpgrade to a fixed release: < 4.14, >= 6.1.188 and <= 6.1.*, >= 6.6.157 and <= 6.6.*, >= 6.12.110 and <= 6.12.* (+3 more below).
Is CVE-2026-90110 being exploited?
Not confirmed. CVE-2026-90110 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.61% probability of exploitation in the next 30 days.
How severe is CVE-2026-90110?
CVE-2026-90110 is rated Critical with a CVSS score of 9.4. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-90110?
Yes. A fix has been recorded for CVE-2026-90110. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-90110 affect?
CVE-2026-90110 affects Linux kernel inetpeer subsystem, Servers and appliances running affected Linux kernels, Network devices using upstream Linux kernel. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-90110?
Apply vendor/upstream kernel updates with the inetpeer fix and reboot affected hosts.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Off‑path attackers can bypass IP‑keyed ICMP/UDP rate limits and infer open UDP ports, enabling reconnaissance and potential abuse of UDP services.
Immediate action required
- affected>= b145425f269a17ed344d737f746b844dfac60c82 and < b20e98f0bb668a59abaf7bcf85d75c073e90d352
- affected>= b145425f269a17ed344d737f746b844dfac60c82 and < 5f127e3cc9647a8a70db12c65dbd0de473545380
- affected>= b145425f269a17ed344d737f746b844dfac60c82 and < 199fcf285e498111e029137d088949bc6c26d578
- affected>= b145425f269a17ed344d737f746b844dfac60c82 and < 857681f6835d5b0a7bc4a34a026baeaaf5215623
- affected>= b145425f269a17ed344d737f746b844dfac60c82 and < 7109bb63667a53e4542ad845476f97d0c8b28a61
- affected>= b145425f269a17ed344d737f746b844dfac60c82 and < 2ee66e9487172fcd189bc52a767c30dad7141c09
- affected4.14
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.
timeline
- 17 Sept 2026Published
- 19 Sept 2026Analysed by vulneraibility.com · 2 days later
- 19 Oct 2026CVE record last updated · 30 days later
- Linkgit.kernel.org /stable/c/b20e98f0bb668a59abaf7bcf85d75c073e90d352
- Linkgit.kernel.org /stable/c/5f127e3cc9647a8a70db12c65dbd0de473545380
- Linkgit.kernel.org /stable/c/199fcf285e498111e029137d088949bc6c26d578
- Linkgit.kernel.org /stable/c/857681f6835d5b0a7bc4a34a026baeaaf5215623
- Linkgit.kernel.org /stable/c/7109bb63667a53e4542ad845476f97d0c8b28a61
- Linkgit.kernel.org /stable/c/2ee66e9487172fcd189bc52a767c30dad7141c09
sources
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- FIRST EPSS: exploit probability and percentile
- Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.