CVE Catalog

CVE-2025-40173

HighCVSS 7.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.14%

4th percentile - higher than 4% of all known CVEs

Summary

In the Linux kernel's IPv6 tunnel (ip6_tunnel), there is no limit on headroom growth, leading to perpetual tunnel expansion. A similar issue in IPv4 has already been fixed.

Risk Assessment

Unbounded headroom growth can lead to kernel memory exhaustion and denial of service (DoS) for other processes.

Recommendation

Apply the Linux kernel patch that introduces a headroom growth limit in the IPv6 tunnel, similar to the existing IPv4 fix.

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: net/ip6_tunnel: Prevent perpetual tunnel growth Similarly to ipv4 tunnel, ipv6 version updates dev->needed_headroom, too. While ipv4 tunnel headroom adjustment growth was limited in commit 5ae1e9922bbd ("net: ip_tunnel: prevent perpetual headroom growth"), ipv6 tunnel yet increases the headroom without any ceiling. Reflect ipv4 tunnel headroom adjustment limit on ipv6 version. Credits to Francesco Ruggeri, who was originally debugging this issue and wrote local Arista-specific patch and a reproducer.

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