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Vulnerability record · CVE-2025-55753 · published 5 December 2025

CVE-2025-55753: Apache http server integer overflow vulnerability

Apache · Http Server

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.

7.5 CVSS 3.1 High EPSS 0.45% · top 63.4% CWE-190 · Integer overflow
7.5CVSS 3.1 base score
0.45%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References
17 Jun 2026Last modified by NVD

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.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://httpd.apache.org/security/vulnerabilities_24.html Vendor Advisory
http://www.openwall.com/lists/oss-security/2025/12/04/4 Issue TrackingThird Party Advisory

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2025-55753), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.