CVE-2026-63992
Critical
Description
In the Linux kernel, the following vulnerability has been resolved: tunnels: do not assume transport header in iptunnel_pmtud_check_icmp() In some cases, iptunnel_pmtud_check_icmp() can be called while skb transport header is not set. This triggers an out-of-bound access, because (typeof(skb->transport_header))~0U is 65535. Access the icmp header based on IPv4 network header, after making sure icmp->type is present in skb linear part. Note that iptunnel_pmtud_check_icmpv6()) is fine.
SeverityCritical
CVSS9.1
Exploit probability—
Product
Linux Kernel
PublishedJul 19, 2026
First seenJul 19, 2026
Weakness typeCWE-125Out-of-bounds read
How to fix
Update
- linux linux_kernel5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.93, 6.18.35, 7.0.12 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| linux linux_kernel | 5.9 ≤ v < 5.10.259, 5.11 ≤ v < 5.15.210, 5.16 ≤ v < 6.1.176, 6.2 ≤ v < 6.6.143, 6.7 ≤ v < 6.12.93, 6.13 ≤ v < 6.18.35, 6.19 ≤ v < 7.0.12, 7.1 | 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.93, 6.18.35, 7.0.12 |
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