CVE-2026-68123: openvswitch: fix GSO userspace truncation underflow

mediumCVSS 5.7CVE-2026-68123

CSIRTS triage

vendor: Linux product: Linux kernel openvswitch Denial of service

What: GSO userspace truncation underflow in openvswitch causes improper packet handling.
Who is affected: Systems running affected Linux kernel versions with openvswitch enabled.
Urgency: Medium priority; denial of service in packet processing.
Action: Apply Linux kernel security patches when available.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: medium — CVSS 5.7
Published: 2026-08-11
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-68123

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-681230.50% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 40% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-68123	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

Recent advisories for openvswitch

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

highCVE-2026-74465: In the Linux kernel, the following vulnerability has been resolved: net: openvswitch: fix pote…nvd · 2026-08-15
unknownCVE-2026-74464: In the Linux kernel, the following vulnerability has been resolved: net: openvswitch: fix skb …nvd · 2026-08-15
highCVE-2026-72253: In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_si…nvd · 2026-08-15
criticalCVE-2026-68123: In the Linux kernel, the following vulnerability has been resolved: openvswitch: fix GSO users…nvd · 2026-08-10
highCVE-2023-5366: Openvswitch don't match packets on nd_target fieldmsrc · 2026-08-06
mediumCVE-2026-64531: net: openvswitch: reject oversized nested action attrsmsrc · 2026-08-06