CVE-2026-43077

Vulnerability

Description

In the Linux kernel's crypto subsystem, the algif_aead interface performs a minimum receive buffer size check during decryption. However, this check incorrectly omits the authentication tag length, leading to a scenario where the allocated buffer may be too small to hold the decrypted plaintext together with the expected tag [1][2]. The oversight originates from a missing addition of the tag size in the size validation logic.

Exploitation

Prerequisites

Exploitation requires the ability to perform AF_ALG operations with AEAD ciphers, typically available to unprivileged users if the algif socket family is accessible. An attacker would craft a decryption request that passes the deficient size check but actually needs a larger buffer, potentially leading to memory corruption or data leak when the kernel writes beyond the allocated buffer [3].

Impact

A successful exploit could allow an attacker to corrupt kernel memory, potentially leading to denial of service or privilege escalation. The exact impact depends on the kernel configuration and the attacker's ability to control the decryption parameters [4].

Mitigation

Patches have been applied to the Linux kernel stable trees in commits [1][2][3][4]. Users should update to the latest stable kernel version containing these fixes. No workaround is available for unpatched systems.