CVE-2025-22029

What it actually does

Race condition in check_unsafe_exec() and execve paths that sets fs->in_exec under cred_guard_mutex but clears it lockless on failure, allowing concurrent threads to observe an inconsistent in_exec==0 state.

Why it matters to the business

May enable local privilege escalation or kernel instability on affected Linux systems, raising the risk of unauthorized code execution or service disruption, particularly in environments with related kernel privilege-escalation activity.

How an attack unfolds

Attacker triggers multiple concurrent execve attempts; one fails after setting in_exec, a second succeeds in setting it, then the first clears the flag, leaving the second thread running with an incorrect state that bypasses intended security checks. Similar race patterns have been leveraged by threat actors in other Linux kernel privilege-escalation exploits.

How to fix it

Update all affected kernel packages to version 0:3.10.0-693.69.1.el7 or newer on Red Hat Enterprise Linux 7.4 systems; apply the vendor-supplied patches that hold cred_guard_mutex while clearing fs->in_exec.

How to confirm the fix worked

Confirm installed kernel version meets or exceeds 3.10.0-693.69.1.el7 via rpm -q or uname -r; verify the patch is present by inspecting fs/exec.c for the mutex-protected clear of in_exec.

Typical attack path

1. Identify systems running vulnerable kernel versions
2. Spawn concurrent execve system calls from an unprivileged process
3. Force one exec to fail after acquiring the cred_guard_mutex
4. Exploit resulting inconsistent fs->in_exec state to escalate privileges

How to detect it

Review audit logs and kernel messages for clusters of failed execve calls followed by unexpected process continuation; correlate with credential-guard mutex activity if extended tracing is enabled.

What your security team should do

• Apply the fixed kernel packages immediately given the prevalence of similar privilege-escalation techniques
• Harden unprivileged execve usage with seccomp or sandboxing where patching is delayed
• Increase monitoring of audit and kernel logs for anomalous exec patterns