CVE-2026-126084: rails · Insufficient Verification of Data Authenticity
Affects railsSource CVE Database V5
Not known to be exploited · CVSS 4.7 Medium : upgrade to 8.1.4.1 or 8.0.5.2 when convenient.
Data as of 10 Nov 2026, 21:20 UTC
Thin evidence
One scorer or none| CNA (GitHub_M) | CVSS 3.1 | 4.7 |
|---|
- Patch
- Available – fixed in 8.1.4.1, 8.0.5.2
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:NExploitation evidence
Disclosed: evidence found.
CVE published 10 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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 10 Nov 2026.
What to do
Upgrade rails to 8.1.4.1 or 8.0.5.2.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| railsrails | Affected
| Fixed in
|
| railsrails | Affected
| Fixed in
|
AI-suggested
Upgrade Rails to version 8.1.4.1 or later, or 8.0.5.2 or later, where this vulnerability is fixed. Applications using the GCS service with cache_control configured should apply these updates to ensure direct-upload URLs are properly signed and validated. No other mitigations are indicated by the vendor advisory.
Description
A vulnerability in Rails Active Storage prior to versions 8.1.4.1 and 8.0.5.2 affects the Google Cloud Storage (GCS) service when configured with the cache_control option. The direct-upload URLs are signed with V4 signatures that cover only certain headers, allowing an attacker to upload files with arbitrary Content-Type headers. This can lead to uploaded objects being served as inline HTML, enabling script execution on the storage origin and potential Service Worker registration scoped to the bucket path. This flaw is fixed in versions 8.1.4.1 and 8.0.5.2.
References
- github.com/rails/rails/security/advisories/GHSA-3w93-6hmw-whh4 (opens in a new tab)
- github.com/rails/rails/commit/8d93f6a872e9550a91bf0e4fce50083a235ef3b1 (opens in a new tab)
- github.com/rails/rails/commit/ddc08ba61a8001e7402864c62e466cf732fc7614 (opens in a new tab)
- github.com/rails/rails/releases/tag/v8.0.5.2 (opens in a new tab)
- github.com/rails/rails/releases/tag/v8.1.4.1 (opens in a new tab)