PT-2026-61125 · Linux · Linux Kernel

CVE-2026-63809 · Published 2026-07-19 · Updated 2026-07-20

Positive Technologies (AI Summary)

CVSS v3.1

7.8

High

Base vector

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

Name of the Vulnerable Software and Affected Versions Linux kernel versions prior to 7.1-rc5

Description Memory corruption can occur in the BPF sysctl handler. The proc sys call handler() function allocates a temporary sysctl buffer using kvzalloc(), which may use vmalloc() for large allocations. However, the buffer is incorrectly freed using kfree(), which is incompatible with vmalloc() allocations. This mismatch can lead to memory corruption. The issue was identified during the analysis of the cgroup bpf run filter sysctl() function.

Recommendations Update the Linux kernel to version 7.1-rc5 or later to ensure the proc sys call handler() function uses kvfree() for buffer deallocation.

Fix

Related Identifiers

CVE-2026-63809

Affected Products

Linux Kernel

References · 11

• https://nvd.nist.gov/vuln/detail/CVE-2026-63809 · Security Note
• https://git.kernel.org/stable/c/77355ef7a9f6b0d2bdf65be3b37f2c1f365e20d2 · Note
• https://git.kernel.org/stable/c/81fc9a13acae99966232f0e055eb2e445263b89a · Note
• https://git.kernel.org/stable/c/4c21b5927d4364bfe7365f2700da5fea0ed0d004 · Note
• https://git.kernel.org/stable/c/838fe9c28121777c59a9406710a68fcf77bb8017 · Note
• https://git.kernel.org/stable/c/e1d1e203a6000804c5d3b8a4aa4e52303c0c7ab2 · Note
• https://git.kernel.org/stable/c/65bd0c0afb0e1bf3287458e342429b069624f7d4 · Note
• https://git.kernel.org/stable/c/d0a81ed5ff5d0f9c3f63a4f9e5a4642c363ecd3e · Note
• https://twitter.com/windowsforum/status/2079105566509498707 · Twitter Post
• https://git.kernel.org/stable/c/70df4de46577fab5e25418f014583155a147c902 · Note
• https://twitter.com/VulmonFeeds/status/2078909956279996481 · Twitter Post