BREW-TRAVIS-CVE-2026-126080 (GHSA-8474-XRP6-WH69)
Vulnerability from osv_homebrew – Published: 2026-11-11 10:06 – Updated: 2026-11-11 10:06 – Source websiteImpact
When constant lookup raises LoadError, ActiveSupport::Inflector#safe_constantize (and String#safe_constantize) builds a regular expression from the requested constant name without escaping it, so a caller that passes untrusted input lets the attacker choose the source of a pattern that the application compiles. Crafted patterns can trigger defects in Ruby's regular expression compiler, possibly leading to a crash of the server process, and repeated requests could keep the application unavailable.
Action Cable passes the channel value of each subscribe command to safe_constantize before any channel lookup, so in the default configuration an unauthenticated client of the Action Cable endpoint can reach this code.
Details
The check that decides whether safe_constantize returns nil or re-raises the LoadError now matches the first segment of the constant name against the error message as a literal string, and no longer compiles a regular expression. It returns the same result as before for constant names that contain no regular expression syntax.
Affected applications
An application is affected if it meets all of these requirements:
- Mounts Action Cable, which a new Rails application does by default at /cable (config.action_cable.mount_path), or otherwise passes untrusted input to safe_constantize.
- Accepts Action Cable connections from untrusted clients. ApplicationCable::Connection#connect authenticates nobody unless the application adds a check.
Workarounds
Applications that do not use Action Cable can set config.action_cable.mount_path = nil to remove the endpoint. Applications that use Action Cable can call reject_unauthorized_connection in ApplicationCable::Connection#connect for unauthenticated clients, which limits exposure to authenticated users but does not remove it.
Releases
The fixed releases are available at the normal locations.
Patches for those who cannot upgrade at once: - 8.1: https://github.com/rails/rails/commit/95aa9e416016524956d4904fed96eaed079580bb.patch - 8.0: https://github.com/rails/rails/commit/210ac22d446c8e2625b091e79256806b836eee20.patch
Versions affected
- activesupport < 8.0.5.2
- activesupport >= 8.1, < 8.1.4.1
Credit
This issue was responsibly reported by Felix Tscheulin (flixt) through HackerOne researcher scheja, and independently by Bucky Wolfe (Igneous), who provided a proof of concept that crashes the server. It was also found by the Anthropic OSS Scanner (ANT-2026-ZUN5KU3Q).
{
"affected": [
{
"ecosystem_specific": {
"fix": null,
"range_state": "affected",
"resource": "activesupport",
"resource_purl": "pkg:gem/activesupport@7.0.8.3",
"upstream_fixed_in": "8.0.5.2"
},
"package": {
"ecosystem": "Homebrew",
"name": "travis",
"purl": "pkg:brew/travis"
},
"ranges": [
{
"events": [
{
"introduced": "1.9.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"database_specific": {
"confidence": "high",
"source": "matched",
"strategy": "registry",
"upstream_evidence": [
{
"ecosystem": "RubyGems",
"key": "pkg:gem/activesupport@7.0.8.3",
"name": "activesupport",
"resource": "activesupport",
"strategy": "registry",
"subject_version": "7.0.8.3"
}
]
},
"details": "### Impact\nWhen constant lookup raises `LoadError`, `ActiveSupport::Inflector#safe_constantize` (and `String#safe_constantize`) builds a regular expression from the requested constant name without escaping it, so a caller that passes untrusted input lets the attacker choose the source of a pattern that the application compiles. Crafted patterns can trigger defects in Ruby\u0027s regular expression compiler, possibly leading to a crash of the server process, and repeated requests could keep the application unavailable.\n\nAction Cable passes the `channel` value of each `subscribe` command to `safe_constantize` before any channel lookup, so in the default configuration an unauthenticated client of the Action Cable endpoint can reach this code.\n\n### Details\nThe check that decides whether `safe_constantize` returns `nil` or re-raises the `LoadError` now matches the first segment of the constant name against the error message as a literal string, and no longer compiles a regular expression. It returns the same result as before for constant names that contain no regular expression syntax.\n\n### Affected applications\nAn application is affected if it meets all of these requirements:\n- Mounts Action Cable, which a new Rails application does by default at `/cable` (`config.action_cable.mount_path`), or otherwise passes untrusted input to `safe_constantize`.\n- Accepts Action Cable connections from untrusted clients. `ApplicationCable::Connection#connect` authenticates nobody unless the application adds a check.\n\n### Workarounds\nApplications that do not use Action Cable can set `config.action_cable.mount_path = nil` to remove the endpoint. Applications that use Action Cable can call `reject_unauthorized_connection` in `ApplicationCable::Connection#connect` for unauthenticated clients, which limits exposure to authenticated users but does not remove it.\n\n### Releases\nThe fixed releases are available at the normal locations.\n\nPatches for those who cannot upgrade at once:\n- 8.1: https://github.com/rails/rails/commit/95aa9e416016524956d4904fed96eaed079580bb.patch\n- 8.0: https://github.com/rails/rails/commit/210ac22d446c8e2625b091e79256806b836eee20.patch\n\n### Versions affected\n\n- activesupport \u003c 8.0.5.2\n- activesupport \u003e= 8.1, \u003c 8.1.4.1\n\n### Credit\nThis issue was responsibly reported by Felix Tscheulin ([flixt](https://hackerone.com/flixt)) through HackerOne researcher [scheja](https://hackerone.com/scheja), and independently by Bucky Wolfe ([Igneous](https://github.com/Igneous)), who provided a proof of concept that crashes the server. It was also found by the Anthropic OSS Scanner (ANT-2026-ZUN5KU3Q).",
"id": "BREW-travis-CVE-2026-126080",
"modified": "2026-11-11T10:06:00Z",
"published": "2026-11-11T10:06:00Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/rails/rails/security/advisories/GHSA-8474-xrp6-wh69"
},
{
"type": "WEB",
"url": "https://github.com/rails/rails/commit/210ac22d446c8e2625b091e79256806b836eee20"
},
{
"type": "WEB",
"url": "https://github.com/rails/rails/commit/95aa9e416016524956d4904fed96eaed079580bb"
},
{
"type": "PACKAGE",
"url": "https://github.com/rails/rails"
},
{
"type": "WEB",
"url": "https://github.com/rails/rails/releases/tag/v8.0.5.2"
},
{
"type": "WEB",
"url": "https://github.com/rails/rails/releases/tag/v8.1.4.1"
},
{
"type": "WEB",
"url": "https://github.com/rubysec/ruby-advisory-db/blob/master/gems/activesupport/GHSA-8474-xrp6-wh69.yml"
}
],
"schema_version": "1.7.3",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
],
"summary": "Active Support: Possible DoS vulnerability in Active Support safe_constantize",
"upstream": [
"GHSA-8474-xrp6-wh69",
"CVE-2026-126080"
]
}
Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline
Sightings and recorded dates, grouped by day · UTC
How durations are calculated
Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.
Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.
Loading timeline…
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.