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VulnerabilityPublished

CVE-2026-126350: Addressable · Regular Expression Denial of Service in templates with certain exploded expressions

Affects mikutterSource GCVE Database

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Authoritative record:CVE-2026-126350· Medium 5.9

Not known to be exploited · CVSS 5.9 Medium : upgrade to 5.0.5 when convenient.

Data as of 13 Nov 2026, 20:04 UTC

CVSS 3.1 base score
5.9Medium
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (GitHub_M)CVSS 3.15.9
Patch
Available – fixed in 5.0.5
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 12 Nov 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: 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 13 Nov 2026.

What to do

Upgrade mikutter to 5.0.5.

Affected software

ProductAffectedFixed in
Homebrewmikutterpkg:brew/mikutterOther threatsAffected
  • >=3.4.6 <5.0.5
Fixed in
  • 5.0.5

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

AI-suggested

Upgrade Addressable to version 2.9.1 or later, which contains the fix for this vulnerability. Alternatively, upgrade to MRI Ruby 3.2 or later if not using JRuby, as these versions have regex engines that mitigate the issue. If upgrading is not immediately possible, avoid matching user-supplied input against vulnerable templates using the explode (*) modifier with the affected operators. Applying a short timeout around calls to Template#match or Template#extract processing untrusted data can also mitigate impact.

Description

Addressable versions from 2.3.0 (excluding yanked 2.3.0 and 2.3.1) through 2.9.0 contain a Regular Expression Denial of Service (ReDoS) vulnerability in URI template matching when using the explode (*) modifier with certain operators. This flaw causes catastrophic backtracking in regex matching, leading to exponential processing time and denial of service when matching maliciously crafted URIs. The issue affects Ruby implementations with non-memoizing regex engines such as MRI Ruby versions before 3.2 and JRuby. It is fixed in Addressable 2.9.1 and in MRI Ruby 3.2 and later. Users only expanding templates or using URI parsing without template matching are not impacted.

References

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