CVE-2025-0577

What it actually does

Insufficient entropy after fork causes getrandom and arc4random family functions to return predictable values when called concurrently with fork.

Why it matters to the business

Weakened cryptographic operations in affected applications may allow attackers to predict tokens, keys, or nonces, increasing risk of credential compromise or session hijacking in high-volume server environments.

How an attack unfolds

An attacker identifies processes that perform fork operations while concurrently invoking getrandom or arc4random, then leverages the resulting predictable randomness to guess cryptographic material generated in child processes.

How to fix it

Upgrade mod_md and related packages to the fixed versions: mod_md 1:2.4.26-3.el10_0.1 (and matching debuginfo/debugsource packages) on Red Hat Enterprise Linux EUS 10.0. Restart affected services after upgrade. Consider library-level patches for glibc if broader exposure exists.

How to confirm the fix worked

Confirm installed package versions match or exceed the fixed releases listed, verify no concurrent fork/randomness patterns remain in application code via static analysis, and test randomness quality post-upgrade using entropy validation tools.

Typical attack path

1. Locate services using fork alongside getrandom/arc4random calls
2. Trigger or observe concurrent fork and randomness generation
3. Collect predictable random outputs from affected child processes
4. Use predicted values to attack dependent cryptographic functions

How to detect it

Review process creation and randomness API call logs around fork events; look for repeated or low-entropy outputs from child processes immediately following forks in services using glibc randomness functions.

What your security team should do

• Apply the specified package updates immediately on all Red Hat Enterprise Linux EUS 10.0 systems running mod_md
• Audit applications for fork patterns combined with randomness generation and refactor to reseed entropy after fork
• Monitor EPSS and exploit maturity indicators for any future increase in risk
• Include this weakness class in cryptographic code reviews for all services