Linux Kernel AF_ALG Socket Race Condition Vulnerability

Technical Analysis

The flaw exists in the kernel's handling of AF_ALG (kernel crypto API) sockets, where lack of proper synchronization during concurrent write operations allows data interleaving and inconsistent internal state. This class of race condition can potentially be leveraged for denial of service, memory corruption, or in worse cases local privilege escalation if attacker-controlled data manipulation leads to exploitable kernel memory states. Exploitation requires local access or the ability to invoke crypto API socket operations, common in containerized or multi-tenant environments. Given its inclusion in CISA KEV, active exploitation has been confirmed in the wild, making unpatched systems a priority target. For organizations running AI agent workloads on shared Linux hosts—including containers performing cryptographic operations, model inference, or tool execution—this vulnerability could allow a malicious or compromised process to escalate privileges or destabilize the host, potentially compromising agent orchestration environments, exposing API keys, or disrupting multi-tenant agent pipelines.

Affected Systems

Linux Kernel versions implementing AF_ALG socket support (crypto API sockets); specific affected version ranges should be confirmed via kernel.org and distribution security advisories (e.g., Red Hat, Debian, Ubuntu, SUSE). Systems exposing AF_ALG functionality to unprivileged or containerized processes are at highest risk.

Indicators of Compromise

• No public file hashes, IPs, or domains associated with this kernel-level vulnerability; exploitation indicators would appear as anomalous AF_ALG socket activity, kernel crash logs, or unexpected process privilege changes in kernel audit logs.

Remediation Steps

1. 1

   Apply Kernel Patches

   Update to the patched Linux kernel version provided by your distribution vendor that resolves the AF_ALG race condition (CVE-2025-39964) as soon as available.

2. 2

   Restrict AF_ALG Access

   Limit access to AF_ALG sockets via seccomp, AppArmor, or SELinux policies, particularly in container runtimes and multi-tenant AI agent execution environments.

3. 3

   Monitor Kernel Logs

   Enable auditing of crypto API socket usage and monitor for crashes, panics, or unusual behavior tied to AF_ALG operations.

4. 4

   Prioritize per CISA KEV Deadline

   Given the September 21, 2026 due date in CISA KEV, treat remediation as urgent and track patch deployment across all Linux-based infrastructure, including agent hosting nodes.

5. 5

   Harden Container Isolation

   For environments running AI agents in containers, ensure kernel-level isolation controls are enforced to prevent host compromise from propagating to agent orchestration layers or exposing credentials/API keys.