High · published December 5, 2025
⚡ An integer overflow could send your ACME certificate renewal requests into an endless loop, like a hamster on a wheel that just can’t stop running! 🐹 Imagine trying to refill a soda machine after it stops working, but instead of pausing to fix it, you keep pressing the button over and over — eventually, it just spills all over the floor. That’s what this overflow issue does to your certificate renewals, creating chaos without any breaks! An attacker could exploit this flaw to cause repeated and rapid certificate renewal requests, which could overwhelm your server’s resources. If left unaddressed, it could lead to downtime or degraded service, leaving your system vulnerable and your users frustrated!
Imagine trying to refill a soda machine after it stops working, but instead of pausing to fix it, you keep pressing the button over and over — eventually, it just spills all over the floor. That’s what this overflow issue does to your certificate renewals, creating chaos without any breaks! This integer overflow occurs in Apache HTTP Server when there are failed attempts to renew ACME certificates. After about 30 days, the backoff timer resets to zero, leading to continuous renewal requests without any delays.
An attacker could exploit this flaw to cause repeated and rapid certificate renewal requests, which could overwhelm your server’s resources. If left unaddressed, it could lead to downtime or degraded service, leaving your system vulnerable and your users frustrated! Upgrade your Apache HTTP Server to version 2.4.66 immediately to fix this integer overflow issue. Additionally, review your ACME certificate renewal configurations to ensure they align with best practices. Don't forget to monitor the server for unusual traffic patterns as a precaution! You've got this! Following these steps will help you secure your server and keep everything running smoothly! 🛡️
| Product | Versions | Fixed in |
|---|---|---|
| apache/http_server | ≥ 2.4.30, < 2.4.66 | 2.4.66 |