PT-2026-27696 · Linux · Linux Kernel

Published 2026-01-01 · Updated 2026-03-27 · CVE-2026-23331

Positive Technologies (AI Summary)

CVSS v3.1

5.5

Medium

Base vector

AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description A flaw exists in the Linux kernel’s UDP handling. Specifically, when a UDP socket is bound to a wildcard address with a non-zero port, connected to an address, and then disconnected, the socket may not be correctly removed from the 4-tuple hash table. This can leave garbage data in the hash table chain. The issue occurs because the udp disconnect() function calls a rehash function that moves the socket to a new slot without properly removing it from the original location. The udp unhash4() function needs to be updated after udp hash4 dec(hslot2) to correctly remove the socket.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Exploit

Related Identifiers

CVE-2026-23331

Affected Products

Linux Kernel

References · 15

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23331.json · Exploit
• https://git.kernel.org/stable/c/6996a2d2d0a64808c19c98002aeb5d9d1b2df6a4 · Patch
• https://osv.dev/vulnerability/DEBIAN-CVE-2026-23331 · Vendor Advisory
• https://osv.dev/vulnerability/UBUNTU-CVE-2026-23331 · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2026-23331 · Vendor Advisory
• https://git.kernel.org/stable/c/b955350778b8715e1b7885179979b3a68221c0fb · Patch
• https://cve.org/CVERecord?id=CVE-2026-23331 · Security Note
• https://security-tracker.debian.org/tracker/CVE-2026-23331 · Vendor Advisory
• https://git.kernel.org/stable/c/3b8f104880c104151f8c30f2f89df81fb59a286c · Patch
• https://ubuntu.com/security/CVE-2026-23331 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-23331 · Security Note
• https://twitter.com/CVEnew/status/2036763517995356657 · Twitter Post
• https://twitter.com/CVEarity/status/2037571111039467768 · Twitter Post
• https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git · Note
• https://git.kernel.org/linus/6996a2d2d0a64808c19c98002aeb5d9d1b2df6a4 · Note