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VulnerabilityPublished Updated

CVE-2025-26042: uptime-kuma · ReDoS

Affects uptime-kumaSource CVE Database V5

0

Not known to be exploited · CVSS 6.0 Medium.

Data as of 26 Oct 2026, 11:42 UTC

CVSS 3.1 base score
6.0Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 33% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 17 Mar 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
GitHublouislam/uptime-kumapkg:github/louislam/uptime-kumaOther threatsAffected
  • =1.23.0
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

To mitigate CVE-2025-26042, European organizations should implement the following specific measures: 1) Restrict administrative access to Uptime Kuma to trusted personnel only and enforce strong authentication mechanisms such as multi-factor authentication (MFA). 2) Implement strict input validation and sanitization on notification creation forms to detect and reject potentially malicious regex patterns or excessively complex strings. 3) Monitor system resource usage closely for unusual CPU spikes that may indicate attempted ReDoS exploitation. 4) Isolate the Uptime Kuma service in a controlled network segment with limited exposure to reduce attack surface. 5) Stay informed about official patches or updates from Uptime Kuma developers and apply them promptly once available. 6) Conduct regular security audits and penetration testing focusing on web interface input handling. 7) Educate administrators about the risks of crafting complex regex patterns and encourage use of safe notification configurations. These targeted actions go beyond generic advice by focusing on access control, input handling, monitoring, and operational best practices specific to this vulnerability.

Description

Uptime Kuma >== 1.23.0 has a ReDoS vulnerability, specifically when an administrator creates a notification through the web service. If a string is provided it triggers catastrophic backtracking in the regular expression, leading to a ReDoS attack.

References

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