CVE-2025-39770: net: gso: Forbid IPv6 TSO with extensions on devices with only IPV6_CSUM

mediumCVSS 5.5CVE-2025-39770

CSIRTS triage

vendor: Linux product: Linux Kernel Denial of service

What: IPv6 TSO with extensions can cause packet processing issues on devices that only support IPV6_CSUM offload.
Who is affected: Systems running Linux kernel with IPv6 TSO enabled on devices with limited checksum offload capabilities.
Urgency: Medium priority; not currently exploited but affects network stability.
Action: Apply kernel patch to forbid IPv6 TSO with extensions on devices lacking full offload support.

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 5.5
Published: 2026-08-06
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-39770

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-2025-397700.33% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 26% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2025-39770	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

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