Use-after-free in Linux kernel - CVE-2026-64132

Vulnerability identifier: #VU138495

CSH Severity: Low

CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-64132

CWE-ID: CWE-416

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a use-after-free in the ipv6 hop-by-hop ioam processing in ipv6_hop_ioam() when handling crafted ipv6 packets that trigger skb_ensure_writable() buffer reallocation. A local user can send a specially crafted packet to cause a denial of service.

The issue occurs because the hdr pointer is not refreshed after the skb data buffer is reallocated, while the trace pointer is recalculated.

Linux kernel
Ubuntu
linux-ibm (Ubuntu package)
linux-azure (Ubuntu package)
linux-aws (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-nvidia-bos (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux-ibm (Ubuntu package) - addressed in versions 7.0.0-1008.8, 7.0.0-1010.10
linux-azure (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1010.10
linux-aws (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1015.15
linux-nvidia (Ubuntu package) - addressed in versions 7.0.0-1016.16, 7.0.0-1016.16~24.04.1
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2016.16

• https://git.kernel.org/stable/c/24de676da63c1122d2c13b0d546238b66d1b4e62
• https://git.kernel.org/stable/c/5af905aa8e91ff8d94572a1e089558f21dcf24ed
• https://git.kernel.org/stable/c/769723124b7c3b2bfea4cf68ad292698b87c8d01
• https://git.kernel.org/stable/c/e46e6bc97fb1f339730ff1ba74267fbf48e7a422

• Use-after-free in Linux kernel ipv6
• Ubuntu update for linux-ibm
• Ubuntu update for linux-azure
• Ubuntu update for linux-aws
• Ubuntu update for linux-nvidia-bos
• Ubuntu update for linux-nvidia