CVE Catalog

CVE-2026-80978

HighCVSS 7.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.13%

3th percentile - higher than 3% of all known CVEs

Summary

In the Linux kernel, IP tunnel devices derive their advertised needed_headroom from lower output devices. A stack of user-created devices can make the derived value exceed the range representable by 16-bit skb header offsets, so once IP output reserves it, skb head expansion can wrap those offsets.

Risk Assessment

Wrapping of skb header offsets can lead to memory corruption or a kernel crash under unusual, deeply nested IP tunnel configurations. It requires a specially crafted device setup.

Recommendation

Update the Linux kernel to a version with the fix capping the advertised needed_headroom at 512 when publishing it from a lower device. Avoid creating deeply nested stacks of IP tunnel devices.

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: cap advertised IP tunnel headroom IP tunnel devices derive their advertised needed_headroom from lower output devices. A stack of user-created devices can make the derived value larger than the 16-bit skb header offsets can represent. Once IP output reserves it, skb head expansion can wrap those offsets. The runtime transmit path already caps a growing needed_headroom at 512. Apply the same cap when tunnel configuration publishes needed_headroom derived from a lower output device. Capping the advertised value is safe: IP tunnel transmit still expands the skb when a packet needs more headroom. A nonsensical stacked configuration can therefore incur an extra reallocation, but it cannot publish an unbounded reservation to upper layers.

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