VulnTideExploited vulnerabilities, by vendor. Data as of .
Not in CISA KEVPublished CVSS 7.5 highEPSS 0.5% probability of exploitation in 30 daysFound by AI: AISLE
Apache

CVE-2025-55753: Apache HTTP Server: mod_md (ACME), unintended retry intervals

Is it exploited?

Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of . If CISA adds it, this page shows it as known exploited.

How likely is exploitation in the next 30 days?
0.5%

EPSS score, percentile 39.1 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?
7.5 High

CVSS v3.1 base score, from CISA's enrichment of the record

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

Advisories and patches (1)

Which versions are affected?

Affected

  • from 2.4.30 to before 2.4.66

Versions by product

Source: CISA KEV 2026.10.29, as of ; FIRST EPSS, as of ; CVE List, as of . About the data.

What to do

Advisories and patches

This summary is based on the CVE record as of . Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

As listed in the CVE record.

Apache Software Foundation Apache HTTP Server
StatusVersions
Affectedfrom 2.4.30 to before 2.4.66

Versions not listed are: unaffected.

Source: CVE List, as of . About the data.

About this vulnerability

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 issu…

Summary: CVE record, as of .

  • CISA has not added CVE-2025-55753 to its Known Exploited Vulnerabilities (KEV) catalog, as of 29 Oct 2026.
  • The CVE record was published on 5 Dec 2025.
  • The CVE record carries a CVSS v3.1 base score of 7.5 (High), taken from CISA's enrichment of the record.
  • FIRST's EPSS model puts the probability of exploitation in the next 30 days at 0.5% (percentile 39.1), as of 29 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
  • CISA's SSVC assessment in the CVE record: exploitation none, automatable no, technical impact partial.
  • The credits in the CVE record name AISLE as finder.

Source: CISA KEV 2026.10.29, as of ; CVE List, as of ; FIRST EPSS, as of . About the data.

Description

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

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.

Source: CVE List, as of . About the data.

Weakness

CWE-190
  • CWE-190: Integer Overflow or Wraparound

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record.

Timeline

DateEvent
CVE record published

Known exploited Apache vulnerabilities

  • CVE-2016-3081: Apache Struts Command Injection Vulnerability (added )
  • CVE-2026-34486: Apache Tomcat Missing Encryption of Sensitive Data Vulnerability (added )
  • CVE-2026-34197: Apache ActiveMQ Improper Input Validation Vulnerability (added )
  • CVE-2024-38475: Apache HTTP Server Improper Escaping of Output Vulnerability (added )
  • CVE-2025-24813: Apache Tomcat Path Equivalence Vulnerability (added )