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.
Published: 2026-07-19
Score: n/a
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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History

Sun, 19 Jul 2026 15:30:00 +0000

Type Values Removed Values Added
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.
Title tunnels: do not assume transport header in iptunnel_pmtud_check_icmp()
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-07-19T14:56:12.528Z

Reserved: 2026-07-19T07:54:57.025Z

Link: CVE-2026-63992

cve-icon Vulnrichment

No data.

cve-icon NVD

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cve-icon Redhat

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cve-icon OpenCVE Enrichment

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