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CVE-2026-36499 Open vSwitch CVE debrief

CVE-2026-36499 is a medium-severity vulnerability in Open vSwitch. A missing upper-bound check in the udpif_set_threads() function of Open vSwitch v3.6.90 allows an attacker with OVSDB write access to request an excessive number of handler or revalidation threads. This can cause a denial of service (DoS) via resource exhaustion. The vulnerability has a CVSS score of 6.5 and is classified as CWE-770.

Vendor
Open vSwitch
Product
Open vSwitch
CVSS
MEDIUM 6.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-04
Original CVE updated
2026-07-22
Advisory published
2026-06-04
Advisory updated
2026-07-22

Who should care

Users of Open vSwitch v3.6.90 who have OVSDB write access.

Technical summary

The vulnerability is caused by a missing upper-bound check in the udpif_set_threads() function of Open vSwitch v3.6.90. This allows an attacker with OVSDB write access to request an excessive number of handler or revalidation threads, leading to a denial of service (DoS) via resource exhaustion.

Defensive priority

medium

Recommended defensive actions

  • Apply the patch or update to a fixed version of Open vSwitch.
  • Restrict OVSDB write access to only those who need it.

Evidence notes

The vulnerability was reported on GitHub.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-36499 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-36499

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-36499 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-36499

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.