CVE Catalog

CVE-2026-43057

HighCVSS 7.5
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.37%

29th percentile - higher than 29% of all known CVEs

Summary

A vulnerability in the Linux kernel's GSO fallback for tunneled traffic with IPV6_CSUM flag was found. Incorrect network header length checking caused tunneled packets with IPv6 extension headers to not fall back to software checksumming, potentially leading to processing errors.

Risk Assessment

The organization may experience incorrect network stack behavior for IPv6 traffic with extensions in tunnels, potentially leading to packet loss or transmission errors.

Recommendation

It is recommended to immediately update the Linux kernel to a version containing the fix (commit addressing this behavior).

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: net: correctly handle tunneled traffic on IPV6_CSUM GSO fallback NETIF_F_IPV6_CSUM only advertises support for checksum offload of packets without IPv6 extension headers. Packets with extension headers must fall back onto software checksumming. Since TSO depends on checksum offload, those must revert to GSO. The below commit introduces that fallback. It always checks network header length. For tunneled packets, the inner header length must be checked instead. Extend the check accordingly. A special case is tunneled packets without inner IP protocol. Such as RFC 6951 SCTP in UDP. Those are not standard IPv6 followed by transport header either, so also must revert to the software GSO path.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS