CVE-2025-55753
mod_md: Apache HTTP Server: mod_md (ACME), unintended retry intervals
Severity
ImportantRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · December 5, 2025
Updated · September 19, 2026
Description
An integer overflow flaw has been discovered in the Apache HTTP server. The 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.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
CVSS / CWE
CVSS 3.1 · 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CWE-190 · Integer Overflow or Wraparound