CVE-2025-55753
HIGH7.5EPSS 0.05%Apache HTTP Server: mod_md (ACME), unintended retry intervals
Published: 12/5/2025Modified: 4/28/2026
Description
An integer overflow in the case of failed ACME certificate renewal leads, after a number of failures (~30 days in default configurations), to the backoff timer becoming 0. Attempts to renew the certificate then are repeated without delays until it succeeds. This issue affects Apache HTTP Server: from 2.4.30 before 2.4.66. Users are recommended to upgrade to version 2.4.66, which fixes the issue.
Affected packages (4)
- Alpine/apache2from 0, < 2.4.66-r0
- Bitnami/apache>= 2.4.30, < 2.4.66
- Debian/apache2from 0, < 2.4.66-1~deb11u1
- Debian/apache2from 0, < 2.4.66-1~deb11u1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N |