CVE-2026-44587 | CarrierWave has a denylisted_content_type bypass via Unescaped Regex Metacharacters

Exp

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.

Published: 2026-06-17 Last update: 2026-06-18 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-44587 is rated Exploit Available (50/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.22%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2026-44587

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2026-44587

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-23 0.34% 0.22% -0.11%
2 2026-06-19 0.37% 0.34% -0.03%
3 2026-06-17 — 0.37% —

Full EPSS history (4 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-44587

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
4.7 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 1.4 [email protected]
6.1 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 2.7 [email protected]

Weakness enumeration for CVE-2026-44587

GitHub Security Advisory for CVE-2026-44587

GHSA-7g26-2qgj-chfg · Severity: medium · Ecosystem: rubygems — CarrierWave has a denylisted_content_type bypass via Unescaped Regex Metacharacters

OS Trackers for CVE-2026-44587

vendor priority summary link
debian not yet assigned CVE-2026-44587 not yet assigned priority: Debian including 1 source packages (ruby-carrierwave), 1 status rows across 1 suites (bookworm): open 1. https://security-tracker.debian.org/tracker/CVE-2026-44587
ubuntu medium CVE-2026-44587 medium priority: Ubuntu including 1 source packages (ruby-carrierwave), 7 status rows across 7 suites (bionic, focal, jammy, noble, questing, resolute, upstream): needs-triage 5, DNE 2. https://ubuntu.com/security/CVE-2026-44587

Affected software / configurations for CVE-2026-44587

Vendor Product Version Raw CPE
carrierwave_project carrierwave < 2.2.7 cpe:2.3:a:carrierwave_project:carrierwave:*:*:*:*:*:ruby:*:*
carrierwave_project carrierwave >= 3.0.0, < 3.1.3 cpe:2.3:a:carrierwave_project:carrierwave:*:*:*:*:*:ruby:*:*

References for CVE-2026-44587

cvelogic Threat Intelligence