PT-2026-36446 · Linux · Linux Kernel

Syzbot · Published 2026-03-30 · Updated 2026-05-02 · CVE-2026-43029

Positive Technologies (AI Summary)

CVSS v2.0

7.8

High

Base vector

AV:N/AC:L/Au:N/C:N/I:N/A:C

Name of the Vulnerable Software and Affected Versions Linux kernel version 6.19.0-rc8

Description A soft lockup can occur in the mptcp recvmsg() function. When receiving data with MSG PEEK and MSG WAITALL flags, the socket buffer (skb) is not removed from the sk receive queue. This causes the sk wait data() function to continuously find available data without performing an actual wait, resulting in an infinite loop and a system soft lockup.

Recommendations Update the Linux kernel to a version where the mptcp recvmsg() function has been patched to include a last parameter for tracking the last peeked socket buffer.

Fix

Improper Locking

Weakness Enumeration

CWE-606

CWE-667

Related Identifiers

BDU:2026-06496

CVE-2026-43029

Affected Products

Linux Kernel

References · 16

• https://nvd.nist.gov/vuln/detail/CVE-2026-43029 · Security Note
• https://osv.dev/vulnerability/UBUNTU-CVE-2026-43029 · Vendor Advisory
• https://osv.dev/vulnerability/BELL-CVE-2026-43029 · Vendor Advisory
• https://security-tracker.debian.org/tracker/CVE-2026-43029 · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2026-43029 · Security Note
• https://bdu.fstec.ru/vul/2026-06496 · Security Note
• https://ubuntu.com/security/CVE-2026-43029 · Vendor Advisory
• https://osv.dev/vulnerability/DEBIAN-CVE-2026-43029 · Vendor Advisory
• https://git.kernel.org/stable/c/5dd8025a49c268ab6b94d978532af3ad341132a7 · Patch
• https://git.kernel.org/stable/c/58b58b9ba89c43914eea90c18928e51852d10c24 · Patch
• https://git.kernel.org/stable/c/de3c248d1b69eaefa2d5b3da4005936dcf590f1b · Patch
• https://feedly.com/cve/CVE-2026-43029 · Note
• https://docs.bell-sw.com/security/cves/CVE-2026-43029 · Note
• https://access.redhat.com/security/cve/cve-2026-43029 · Note
• https://lore.kernel.org/linux-cve-announce/2026050100-CVE-2026-43029-5cdf@gregkh · Note