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TI-2025-35173 Aliases CVE-2025-55753GHSA-3j5h-f552-7rhh

Apache HTTP Server: mod_md (ACME), unintended retry intervals

Priority LOW 33CWE-190Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · None · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00483 41st percentileScored 2026-11-07
Fix Fixed Apache HTTP Server (Apache Software Foundation): 2.4.66Red Hat: 14 advisories

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
ApacheApache HTTP Server2.4.30 to before 2.4.662.4.66Patch availableCNA
  • Apache HTTP Server VendorApache Affected 2.4.30 to before 2.4.66 Fixed in 2.4.66 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*2.4.30 to before 2.4.66VulnerableApache
  • cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:* Versions 2.4.30 to before 2.4.66 Vulnerable ·Apache

Remediation

  • Fix · CNA Apache HTTP Server (Apache Software Foundation) Fixed in 2.4.66

Red Hat 14 advisories

  • RHSA-2026:2994 Released 2026-02-23 · Red Hat rating Important
    Red Hat JBoss Core Services Apache HTTP Server 2.4.62 SP3 security update
    • Red Hat JBoss Core Services on RHEL 7 Server jbcs-httpd24-apr-util-1.6.3-4.el7jbcs, jbcs-httpd24-apr-util-devel-1.6.3-4.el7jbcs, jbcs-httpd24-apr-util-ldap-1.6.3-4.el7jbcs +31
    • Red Hat JBoss Core Services on RHEL 8 jbcs-httpd24-apr-util-1.6.3-4.el8jbcs, jbcs-httpd24-apr-util-devel-1.6.3-4.el8jbcs, jbcs-httpd24-apr-util-ldap-1.6.3-4.el8jbcs +21
  • RHSA-2026:2995 Released 2026-02-23 · Red Hat rating Important
    Red Hat JBoss Core Services Apache HTTP Server 2.4.62 SP3 security update
    • Red Hat JBoss Core Services 2.4.62.SP3
  • RHSA-2026:0094 Released 2026-01-06 · Red Hat rating Important
    mod_md security update
    • Red Hat Enterprise Linux AppStream EUS (v.9.6) mod_md-1:2.4.26-1.el9_6.1
Show 11 more Red Hat advisories
  • RHSA-2026:0093 Released 2026-01-06 · Red Hat rating Important
    mod_md security update
    • Red Hat Enterprise Linux AppStream EUS (v. 10.0) mod_md-1:2.4.26-3.el10_0.1
  • RHSA-2026:0092 Released 2026-01-06 · Red Hat rating Important
    mod_md security update
    • Red Hat Enterprise Linux AppStream E4S (v.9.0) mod_md-1:2.4.0-3.el9_0.1
  • RHSA-2026:0029 Released 2026-01-05 · Red Hat rating Important
    mod_md security update
    • Red Hat Enterprise Linux AppStream EUS (v.9.4) mod_md-1:2.4.19-1.el9_4.1
  • RHSA-2026:0030 Released 2026-01-05 · Red Hat rating Important
    mod_md security update
    • Red Hat Enterprise Linux AppStream E4S (v.9.2) mod_md-1:2.4.19-1.el9_2.1
  • RHSA-2026:0012 Released 2026-01-05 · Red Hat rating Important
    httpd:2.4 security update
    • Red Hat Enterprise Linux AppStream E4S (v.8.8) httpd-2.4.37-56.module+el8.8.0+23840+d7e7db80.11.ppc64le::httpd:2.4, httpd-2.4.37-56.module+el8.8.0+23840+d7e7db80.11.src::httpd:2.4, httpd-2.4.37-56.module+el8.8.0+23840+d7e7db80.11.x86_64::httpd:2.4 +20
    • Red Hat Enterprise Linux AppStream TUS (v.8.8) httpd-2.4.37-56.module+el8.8.0+23840+d7e7db80.11.src::httpd:2.4, httpd-2.4.37-56.module+el8.8.0+23840+d7e7db80.11.x86_64::httpd:2.4, httpd-devel-2.4.37-56.module+el8.8.0+23840+d7e7db80.11.x86_64::httpd:2.4 +11
  • RHSA-2026:0011 Released 2026-01-05 · Red Hat rating Important
    httpd:2.4 security update
    • Red Hat Enterprise Linux AppStream AUS (v.8.6) httpd-2.4.37-47.module+el8.6.0+23843+c27a5dc4.12.src::httpd:2.4, httpd-2.4.37-47.module+el8.6.0+23843+c27a5dc4.12.x86_64::httpd:2.4, httpd-devel-2.4.37-47.module+el8.6.0+23843+c27a5dc4.12.x86_64::httpd:2.4 +11
    • Red Hat Enterprise Linux AppStream E4S (v.8.6) httpd-2.4.37-47.module+el8.6.0+23843+c27a5dc4.12.aarch64::httpd:2.4, httpd-2.4.37-47.module+el8.6.0+23843+c27a5dc4.12.ppc64le::httpd:2.4, httpd-2.4.37-47.module+el8.6.0+23843+c27a5dc4.12.s390x::httpd:2.4 +38
    • Red Hat Enterprise Linux AppStream TUS (v.8.6) httpd-2.4.37-47.module+el8.6.0+23843+c27a5dc4.12.src::httpd:2.4, httpd-2.4.37-47.module+el8.6.0+23843+c27a5dc4.12.x86_64::httpd:2.4, httpd-devel-2.4.37-47.module+el8.6.0+23843+c27a5dc4.12.x86_64::httpd:2.4 +11
  • RHSA-2026:0010 Released 2026-01-05 · Red Hat rating Important
    httpd:2.4 security update
    • Red Hat Enterprise Linux AppStream AUS (v.8.4) httpd-2.4.37-39.module+el8.4.0+23842+00253415.11.src::httpd:2.4, httpd-2.4.37-39.module+el8.4.0+23842+00253415.11.x86_64::httpd:2.4, httpd-devel-2.4.37-39.module+el8.4.0+23842+00253415.11.x86_64::httpd:2.4 +11
    • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) httpd-2.4.37-39.module+el8.4.0+23842+00253415.11.src::httpd:2.4, httpd-2.4.37-39.module+el8.4.0+23842+00253415.11.x86_64::httpd:2.4, httpd-devel-2.4.37-39.module+el8.4.0+23842+00253415.11.x86_64::httpd:2.4 +11
  • RHSA-2026:0009 Released 2026-01-05 · Red Hat rating Important
    httpd:2.4 security update
    • Red Hat Enterprise Linux AppStream AUS (v. 8.2) httpd-2.4.37-21.module+el8.2.0+23841+60fa4803.11.src::httpd:2.4, httpd-2.4.37-21.module+el8.2.0+23841+60fa4803.11.x86_64::httpd:2.4, httpd-devel-2.4.37-21.module+el8.2.0+23841+60fa4803.11.x86_64::httpd:2.4 +11
  • RHSA-2025:23739 Released 2025-12-22 · Red Hat rating Important
    mod_md security update
    • Red Hat Enterprise Linux AppStream (v. 9) mod_md-1:2.4.26-1.el9_7.1
  • RHSA-2025:23732 Released 2025-12-22 · Red Hat rating Important
    httpd:2.4 security update
    • Red Hat Enterprise Linux AppStream (v. 8) httpd-2.4.37-65.module+el8.10.0+23815+1b5e1c66.7.aarch64::httpd:2.4, httpd-2.4.37-65.module+el8.10.0+23815+1b5e1c66.7.ppc64le::httpd:2.4, httpd-2.4.37-65.module+el8.10.0+23815+1b5e1c66.7.s390x::httpd:2.4 +38
  • RHSA-2025:23738 Released 2025-12-22 · Red Hat rating Important
    mod_md security update
    • Red Hat Enterprise Linux AppStream (v. 10) mod_md-1:2.4.26-4.el10_1

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    Apache HTTP Server 2.4.66

    2 records Highest priority Priority MEDIUM 1 MEDIUM, 1 LOW

    Other records, highest priority first

    • TI-2025-35937 Apache HTTP Server: Server Side Includes adds query string to #exec cmd=...Priority MEDIUM 41
    Show all 2 records →

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2025:23738
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2025:23732
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2025:23739
Red Hat Enterprise Linux AppStream AUS (v. 8.2)Fixed RHSA-2026:0009
Red Hat Enterprise Linux AppStream AUS (v.8.4)Fixed RHSA-2026:0010
Red Hat Enterprise Linux AppStream AUS (v.8.6)Fixed RHSA-2026:0011
Red Hat Enterprise Linux AppStream E4S (v.8.6)Fixed RHSA-2026:0011
Red Hat Enterprise Linux AppStream E4S (v.8.8)Fixed RHSA-2026:0012
Red Hat Enterprise Linux AppStream E4S (v.9.0)Fixed RHSA-2026:0092
Red Hat Enterprise Linux AppStream E4S (v.9.2)Fixed RHSA-2026:0030
Red Hat Enterprise Linux AppStream EUS (v. 10.0)Fixed RHSA-2026:0093
Red Hat Enterprise Linux AppStream EUS (v.9.4)Fixed RHSA-2026:0029
Red Hat Enterprise Linux AppStream EUS (v.9.6)Fixed RHSA-2026:0094
Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4)Fixed RHSA-2026:0010
Red Hat Enterprise Linux AppStream TUS (v.8.6)Fixed RHSA-2026:0011
Red Hat Enterprise Linux AppStream TUS (v.8.8)Fixed RHSA-2026:0012
Red Hat JBoss Core Services 2.4.62.SP3Fixed RHSA-2026:2995
Red Hat JBoss Core Services on RHEL 7 ServerFixed RHSA-2026:2994
Red Hat JBoss Core Services on RHEL 8Fixed RHSA-2026:2994
Not affected: 4 products
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat JBoss Core Services on RHEL 7 Server
  • Red Hat JBoss Core Services on RHEL 8

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-55753
  2. 2026-10-03 Alias added: GHSA-3j5h-f552-7rhh
  3. 2026-10-09 Fix available: RHSA-2026:2995 · Red Hat
  4. 2026-11-05 Fix available: Red Hat JBoss Core Services 2.4.62.SP3 · Red Hat

References

Advisory 2

  • TI-2021-18535 Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) KEVCVSS 3.1CRITICAL 9.8
  • TI-2021-18417 Path traversal and file disclosure vulnerability in Apache HTTP Server 2.4.49 KEVCVSS 3.1CRITICAL 9.8
  • TI-2024-25716 Apache HTTP Server weakness in mod_rewrite when first segment of substitution matches filesystem path. KEVCVSS 3.1CRITICAL 9.1
  • TI-2021-17490 mod_proxy SSRF KEVCVSS 3.1CRITICAL 9.0
  • TI-2019-00184 Use after free in Apache HTTP Server KEVCVSS 3.1HIGH 7.8
  • TI-2009-03392 The TLS protocol, and the SSL protocol 3.0 and possibly earlier, as used in Microsoft… CVSS 3.1CRITICAL 9.8
See all 349 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences