Use-after-free in Linux kernel - CVE-2026-63922
Published: July 20, 2026
Vulnerability identifier: #VU138727
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-63922
CWE-ID: CWE-416
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Linux Foundation
Affected software:
Linux kernel
Linux kernel
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to a use-after-free risk from stale pointer reuse in ip6_parse_tlv() in net/ipv6/exthdrs.c when parsing IPv6 TLVs containing the HAO option. A remote attacker can send a specially crafted IPv6 packet to cause a denial of service.
The issue occurs when handling a cloned skb where header expansion moves the skb head and invalidates the cached network header pointer.
How to mitigate CVE-2026-63922
Install security update from vendor's repository.
Sources
- https://git.kernel.org/stable/c/12d957979e4a800167842f1b42be6a606d227ebe
- https://git.kernel.org/stable/c/1a11eb7431e3d2882f5bd5939c5a9bbc65ccf4d1
- https://git.kernel.org/stable/c/751db1b802a067b7fff25880f4e9f9152a171538
- https://git.kernel.org/stable/c/9b6dcc0a39fd71752937f0b6b3973e1416085dcf
- https://git.kernel.org/stable/c/f7b52afe3592eae66e160586b45a3f2242972c63
- https://git.kernel.org/stable/c/f8aabed3ff3e986920cf02a2a2785e08e586b234
- https://git.kernel.org/stable/c/ff375ed1cba81392346c5bfbf0bb7a13b2946f99