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CVE-2026-126080VulnerabilityPublished Updated

Rails: Prior to 8.1.4.1 and 8.0.5.2, when constant lookup raises LoadError, ActiveSupport::Inflector#safe_constantize

Affects railsSource GCVE Database

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Authoritative record:CVE-2026-126080· High 7.5

Not known to be exploited · CVSS 7.5 High · fixed in 8.1.4.1 : patch rails soon.

Data as of 13 Nov 2026, 22:24 UTC

CVSS 3.1 base score
7.5High
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 3.17.5
Patch
Available – fixed in 8.1.4.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 10 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

Affected software

ProductAffectedFixed in
Ubuntu 26.10railspkg:deb/ubuntu/rails?arch=source&distro=stonkingOther threatsAffected
  • =2:7.2.3+dfsg-2
  • =2:7.2.3.2+dfsg-2
Fixed in–
Ubuntu 26.04 LTSrailspkg:deb/ubuntu/rails?arch=source&distro=resoluteOther threatsAffected
  • =2:7.2.2.1+dfsg-7
  • =2:7.2.2.2+dfsg-2
  • =2:7.2.3+dfsg-2
Fixed in–
Ubuntu 24.04 LTSrailspkg:deb/ubuntu/rails?arch=source&distro=nobleOther threatsAffected
  • =2:6.1.7.3+dfsg-2build1
  • =2:6.1.7.3+dfsg-3
Fixed in–
Ubuntu Pro 22.04 LTSrailspkg:deb/ubuntu/rails?arch=source&distro=esm-apps/jammyOther threatsAffected
  • =2:6.0.3.7+dfsg-2
  • =2:6.1.4.1+dfsg-8ubuntu2
  • =2:6.1.4.1+dfsg-8ubuntu2+esm1
Fixed in–
Ubuntu Pro 20.04 LTSrailspkg:deb/ubuntu/rails?arch=source&distro=esm-apps/focalOther threatsAffected
  • =2:5.2.2.1+dfsg-1ubuntu1
  • =2:5.2.3+dfsg-3
  • =2:5.2.3+dfsg-3ubuntu0.1~esm1
Fixed in–
Ubuntu Pro 18.04 LTSrailspkg:deb/ubuntu/rails?arch=source&distro=esm-apps/bionicOther threatsAffected
  • 2:4.2.9-2 – 2:4.2.10-0ubuntu4+esm2
5 affected builds
Fixed in–

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

AI-suggested

Upgrade Rails to version 8.1.4.1 or 8.0.5.2 or later, where this issue is fixed. Additionally, ensure that Action Cable connections are authenticated to prevent unauthenticated clients from triggering this vulnerability. No other mitigations are specified.

Description

A vulnerability in Rails Active Support prior to versions 8.1.4.1 and 8.0.5.2 allows an attacker to cause a server crash by passing crafted input to ActiveSupport::Inflector#safe_constantize, which improperly builds a regular expression without escaping. This can lead to denial of service via repeated crashes. The issue affects applications using Action Cable that accept unauthenticated client connections without additional authentication checks. The vulnerability is fixed in versions 8.1.4.1 and 8.0.5.2.

References

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