CVE-2026-63993
Published: July 22, 2026Last modified: July 22, 2026
Description
In the Linux kernel, the following vulnerability has been resolved: vxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu() skb_tunnel_check_pmtu() can change skb->head. Reusing old_iph afer skb_tunnel_check_pmtu() can cause an UAF. Use instead ip_hdr(skb) as done in drivers/net/bareudp.c and drivers/net/geneve.c. Found by Sashiko.
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 9.8 |
| Attack Vector | NETWORK |
| Attack complexity | LOW |
| Privileges required | NONE |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | HIGH |
| Integrity impact | HIGH |
| Availability impact | HIGH |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | linux-lts | Fixed (6.1.177-r0) |
| 25 LTS | linux-lts | Fixed (6.12.95-r0) | |
| Stream | linux-lts | Fixed (6.18.35-r1) |
References
- https://git.kernel.org/stable/c/5303925e360527243b46a440a04667826bbc72b7
- https://git.kernel.org/stable/c/609e63312c29aad18026a1d3222e123d4b6b0feb
- https://git.kernel.org/stable/c/6b8bfce9d2f774d2c2243e0248e03efb99bba6c0
- https://git.kernel.org/stable/c/7d9ef0cb271555d8cf39fefe6c981e1493b25ecf
- https://git.kernel.org/stable/c/8d435d68d71fb875876b722f4136caf74f2f48bd
- https://git.kernel.org/stable/c/9257f56ac47ef1976bcd056cf986a9988eeec67a
- https://git.kernel.org/stable/c/a493efd4336cf19122ae0e4cbb3d31b32d70deea
- https://git.kernel.org/stable/c/dc3bfa050f873371e745bdf478b1f5b738e5733d