CVE-2026-63994: tunnels: load network headers after skb_cow() in iptunnel_pmtud_build_icmp[v6]()
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
In iptunnel_pmtud_build_icmp() and iptunnel_pmtud_build_icmpv6(), initialize the local variables and load ip_hdr() and ipv6_hdr() only after the skb_cow() call; remove the unnecessary skb_reset_network_header() calls.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-63994?
The severity of CVE-2026-63994 is critical with a score of 9.8.
How does CVE-2026-63994 affect the Linux kernel?
CVE-2026-63994 involves the loading of network headers after skb_cow() in the iptunnel_pmtud_build_icmp() and iptunnel_pmtud_build_icmpv6() functions.
How can CVE-2026-63994 be mitigated?
Mitigation for CVE-2026-63994 involves applying the appropriate updates or patches to the Linux kernel.
Is CVE-2026-63994 exploitable remotely?
Yes, CVE-2026-63994 is classified as having network access (AV:N), making it potentially exploitable remotely.
What types of damage can CVE-2026-63994 cause?
CVE-2026-63994 allows for potential high impact on confidentiality, integrity, and availability due to its critical nature.