Vulnerability · Published Dec 5, 2025 · Assigned by apache
CVE-2025-55753Apache HTTP Server: mod_md (ACME), unintended retry intervals
High 7.5
In plain English
A high-severity integer overflow in Apache HTTP Server from Apache Software Foundation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 42% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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 & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:8 | httpd | 2.4.37-65.module_el8.10.0+4088+57f011c1.7 | ALSA-2025:23732 |
| AlmaLinux:8 | httpd-devel | 2.4.37-65.module_el8.10.0+4088+57f011c1.7 | ALSA-2025:23732 |
| AlmaLinux:8 | httpd-filesystem | 2.4.37-65.module_el8.10.0+4088+57f011c1.7 | ALSA-2025:23732 |
| AlmaLinux:8 | httpd-manual | 2.4.37-65.module_el8.10.0+4088+57f011c1.7 | ALSA-2025:23732 |
| AlmaLinux:8 | httpd-tools | 2.4.37-65.module_el8.10.0+4088+57f011c1.7 | ALSA-2025:23732 |
| AlmaLinux:8 | mod_http2 | 1.15.7-10.module_el8.10.0+4044+ea5f78b1.4 | ALSA-2025:23732 |
| AlmaLinux:8 | mod_ldap | 2.4.37-65.module_el8.10.0+4088+57f011c1.7 | ALSA-2025:23732 |
| AlmaLinux:10 | mod_md | 1:2.4.26-4.el10_1 | ALSA-2025:23738 |
| AlmaLinux:8 | mod_md | 1:2.0.8-8.module_el8.10.0+4088+57f011c1.2 | ALSA-2025:23732 |
| AlmaLinux:9 | mod_md | 1:2.4.26-1.el9_7.1 | ALSA-2025:23739 |
| AlmaLinux:8 | mod_proxy_html | 1:2.4.37-65.module_el8.10.0+4088+57f011c1.7 | ALSA-2025:23732 |
| AlmaLinux:8 | mod_session | 2.4.37-65.module_el8.10.0+4088+57f011c1.7 | ALSA-2025:23732 |
| AlmaLinux:8 | mod_ssl | 1:2.4.37-65.module_el8.10.0+4088+57f011c1.7 | ALSA-2025:23732 |
| Alpine:v3.20 | apache2 | 2.4.66-r0 | ALPINE-CVE-2025-55753 |
| Alpine:v3.21 | apache2 | 2.4.66-r0 | ALPINE-CVE-2025-55753 |
| Alpine:v3.22 | apache2 | 2.4.66-r0 | ALPINE-CVE-2025-55753 |
| Alpine:v3.23 | apache2 | 2.4.66-r0 | ALPINE-CVE-2025-55753 |
| Alpine:v3.24 | apache2 | 2.4.66-r0 | ALPINE-CVE-2025-55753 |
| Debian:12 | apache2 | 2.4.66-1~deb12u1 | DEBIAN-CVE-2025-55753 |
| Debian:13 | apache2 | 2.4.66-1~deb13u1 | DEBIAN-CVE-2025-55753 |
| Debian:14 | apache2 | 2.4.66-1 | DEBIAN-CVE-2025-55753 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+1938+3b7755d4.3 | RLSA-2025:23732 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+1840+b070a976.1 | RLSA-2025:23732 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+1984+1bed3124.4 | RLSA-2025:23732 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+2061+8d03fdec.5 | RLSA-2025:23732 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+40045+6ce8579b.6 | RLSA-2025:23732 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+1842+4a9649e8.2 | RLSA-2025:23732 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+1830+22f0c9e0 | RLSA-2025:23732 |
| Rocky Linux:8 | mod_http2 | 0:1.15.7-10.module+el8.10.0+1775+6b057638 | RLSA-2025:23732 |
| Rocky Linux:8 | mod_http2 | 0:1.15.7-10.module+el8.10.0+1830+22f0c9e0 | RLSA-2025:23732 |
| Rocky Linux:8 | mod_http2 | 0:1.15.7-10.module+el8.10.0+1938+3b7755d4.3 | RLSA-2025:23732 |
| Rocky Linux:8 | mod_http2 | 0:1.15.7-10.module+el8.10.0+1883+38ed6c58.1 | RLSA-2025:23732 |
| Rocky Linux:8 | mod_http2 | 0:1.15.7-10.module+el8.10.0+2061+8d03fdec.4 | RLSA-2025:23732 |
| Rocky Linux:10 | mod_md | 1:2.4.26-4.el10_1 | RLSA-2025:23738 |
| Rocky Linux:8 | mod_md | 1:2.0.8-8.module+el8.9.0+1370+89cc8ad5 | RLSA-2025:23732 |
| Rocky Linux:9 | mod_md | 1:2.4.26-1.el9_7.1 | RLSA-2025:23739 |
| Ubuntu:22.04:LTS | apache2 | 2.4.52-1ubuntu4.18 | USN-7968-1 |
| Ubuntu:22.04:LTS | apache2 | 2.4.52-1ubuntu4.18 | UBUNTU-CVE-2025-55753 |
| Ubuntu:24.04:LTS | apache2 | 2.4.58-1ubuntu8.10 | UBUNTU-CVE-2025-55753 |
| Ubuntu:24.04:LTS | apache2 | 2.4.58-1ubuntu8.10 | USN-7968-1 |
| Ubuntu:25.10 | apache2 | 2.4.64-1ubuntu3.2 | USN-7968-1 |
| Ubuntu:25.10 | apache2 | 2.4.64-1ubuntu3.2 | UBUNTU-CVE-2025-55753 |
| Ubuntu:26.04:LTS | apache2 | 2.4.66-2ubuntu1 | UBUNTU-CVE-2025-55753 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Apache Software Foundation | Apache HTTP Server | 2.4.30 – before 2.4.66 |
Weakness: CWE-190 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N