CVE-2026-63992: tunnels: do not assume transport header in iptunnel_pmtud_check_icmp()
In the Linux kernel, the following vulnerability has been resolved:
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
debian/linuxto a version that resolves this vulnerability.Fixed in 6.1.176-1Fixed in 6.1.187-1Fixed in 6.12.107-1Fixed in 6.12.111-1Fixed in 7.2.8-1Fixed in 7.2.9-1 - Compensating control
Update iptunnel_pmtud_check_icmp() so it accesses the ICMP header based on the IPv4 network header rather than assuming skb->transport_header is set, and first ensure icmp->type is present in the skb linear part.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-63992?
CVE-2026-63992 has a critical severity rating of 9.1.
How do I fix CVE-2026-63992?
To fix CVE-2026-63992, update your Linux kernel to the latest patched version that addresses this vulnerability.
What type of vulnerability is CVE-2026-63992?
CVE-2026-63992 is an out-of-bounds access vulnerability in the iptunnel_pmtud_check_icmp() function in the Linux kernel.
What are the potential impacts of CVE-2026-63992?
CVE-2026-63992 could lead to kernel crashes or other unintended behavior due to out-of-bounds memory access.
Which software is affected by CVE-2026-63992?
CVE-2026-63992 affects the Linux kernel.