Incomplete cleanup in Linux kernel - CVE-2026-98595

Vulnerability identifier: #VU156899

CSH Severity: Low

CVSS v4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-98595

CWE-ID: CWE-459

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to cause an IPv6 UDP datagram to match a disconnected socket through stale peer-address state.

The vulnerability exists due to incomplete cleanup of the IPv6 peer address in the Linux kernel __udp_disconnect() function when disconnecting an IPv6 UDP socket. A remote attacker can send a datagram from the former peer with source port zero to match a disconnected socket whose stale entry remains in the 4-tuple hash table, potentially causing unintended packet delivery.

Linux kernel
Ubuntu
linux (Ubuntu package)
linux-aws (Ubuntu package)
linux-gcp (Ubuntu package)
linux-oracle (Ubuntu package)
linux-ibm (Ubuntu package)
linux-hwe-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux (Ubuntu package) - update to 7.0.0-42.42
linux-aws (Ubuntu package) - update to 7.0.0-1016.17
linux-gcp (Ubuntu package) - update to 7.0.0-1016.18
linux-oracle (Ubuntu package) - update to 7.0.0-1015.16
linux-ibm (Ubuntu package) - update to 7.0.0-1017.17
linux-hwe-7.0 (Ubuntu package) - update to 7.0.0-42.42~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1017.17

• https://git.kernel.org/stable/c/9e95b1a94c9c49b4ba722251bbca2759b9c51737
• https://git.kernel.org/stable/c/c21daf37d5ce9a4e234b7c42238ac1e6041e28e4
• https://git.kernel.org/stable/c/d1b5fd969cc53f29d02b82b05a45135de4a6087a

• Incomplete cleanup in Linux kernel ipv4
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more