SEPTEMBER 14, 2026
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Case File

CVE-2026-80978

HIGH · CVSS 7.8 EPSS 0.13%

Source: NVD + CISA KEV + EPSS · Published 2026-09-11 · Last synced 2026-09-14

CyberRota Analysis

AI-Generated

The vulnerability affects the Linux kernel's handling of IP tunnel devices, where user-created device stacks can lead to an overflow in the advertised needed_headroom value, potentially causing memory management issues. This could result in unexpected behavior during packet transmission, although the impact is mitigated by existing caps on headroom. Organizations using Linux-based systems, particularly those utilizing IP tunneling, should prioritize addressing this issue to prevent potential disruptions in network performance.

CVE
CVE-2026-80978
Severity
HIGH
CVSS
7.8
EPSS
0.13%
Linux

Original NVD Description

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.