Status: UPDATED | Advisory ID: CVE-2026-63994
| CVE | CVE-2026-63994 |
| CVSS Score / Version | 9.8 (Critical) / CVSS v3.1 |
| Updated | 2026-10-07 |
| CVSS Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| CVSS Prose | attack vector is network; attack complexity is low; privileges required is none; user interaction is none; scope is unchanged; confidentiality impact is high; integrity impact is high; availability impact is high. |
| Affected products | Linux Kernel |
| Classified as | CWE-416 (Use After Free) |
| Vendor | Product | Affected Versions | Patch Status |
|---|---|---|---|
| Linux | Linux Kernel |
| Subsystems | OT Supporting Infrastructure |
| Sectors | All Sectors |
In the Linux kernel, the following vulnerability has been resolved:
tunnels: load network headers after skb_cow() in iptunnel_pmtud_build_icmp[v6]()
Sashiko found that iptunnel_pmtud_build_icmp() and
iptunnel_pmtud_build_icmpv6() were caching ip_hdr() and ipv6_hdr()
before an skb_cow() call which can reallocate skb->head.
Fix this possible UAF by initializing the local variables
after the skb_cow() call.
Remove skb_reset_network_header() calls which were not needed. (NVD)
Monitor Linux's web page for any future patch releases.
| Source | Reference |
|---|---|
| NVD | https://nvd.nist.gov/vuln/detail/CVE-2026-63994 |
| CVE | https://www.cve.org/CVERecord?id=CVE-2026-63994 |