Integer overflow in Apache HTTP Server
CVE-2025-55753
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.
Vulnerability class: Integer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.
EPSS exploit prediction
EPSS: 0.004 (36.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 37th percentile — 36.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: +0.000
Affected products
- Apache HTTP Server
- Apache Software Foundation HTTP Server — versions 2.4.30
Weakness classification (CWE)
References
- httpd.apache.org/security/vulnerabilities_24.html (vendor-advisory, Vendor Advisory)
- af854a3a-2127-422b-91ae-364da2661108 (Issue Tracking, Third Party Advisory)
Frequently asked questions
- What is CVE-2025-55753?
- CVE-2025-55753 is a high-severity vulnerability in Apache HTTP Server, classified under Integer Overflow or Wraparound. CVSS score: 7.5/10. Published 2025-12-05.
- How severe is CVE-2025-55753?
- High severity. CVSS v3 base score is 7.5 out of 10.