Rails: Prior to 8.1.4.1 and 8.0.5.2, ActionController::Live::Buffer#close pushes its end-of-stream marker onto the
Affects railsSource GCVE Database
Not known to be exploited · CVSS 5.9 Medium · fixed in 8.1.4.1 : update rails when convenient.
Data as of 13 Nov 2026, 22:32 UTC
Thin evidence
One scorer or none| CNA (GitHub_M) | CVSS 3.1 | 5.9 |
|---|
- Patch
- Available – fixed in 8.1.4.1
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation 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 13 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10railspkg:deb/ubuntu/rails?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSrailspkg:deb/ubuntu/rails?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSrailspkg:deb/ubuntu/rails?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu Pro 22.04 LTSrailspkg:deb/ubuntu/rails?arch=source&distro=esm-apps/jammyOther threats | Affected
| Fixed in– |
Ubuntu Pro 20.04 LTSrailspkg:deb/ubuntu/rails?arch=source&distro=esm-apps/focalOther threats | Affected
| Fixed in– |
Ubuntu Pro 18.04 LTSrailspkg:deb/ubuntu/rails?arch=source&distro=esm-apps/bionicOther threats | Affected
| 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 Ruby on Rails to version 8.1.4.1 or 8.0.5.2 or later, where this issue is fixed. No other mitigations are indicated by the vendor advisory.
Description
A denial-of-service vulnerability exists in Ruby on Rails versions prior to 8.1.4.1 and 8.0.5.2 in the ActionController::Live::Buffer component. The issue occurs when the buffer's end-of-stream marker push blocks due to a full response queue while holding a monitor, causing threads to wait indefinitely and potentially exhaust server threads. This affects applications streaming responses with ActionController::Live, including send_stream, and those serving large files via Active Storage proxy mode. The vulnerability is fixed in versions 8.1.4.1 and 8.0.5.2.
References
- ubuntu.com/security/CVE-2026-126072 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-126072 (opens in a new tab)
- github.com/rails/rails/security/advisories/GHSA-rwvh-fw6r-pwvp (opens in a new tab)
- github.com/rails/rails/commit/27ad18ed5900dee28ba20e9c6fc718ff751fa215 (opens in a new tab)
- github.com/rails/rails/commit/ccbfc09690fef05fdd2a9969c917a71b92cc98fc (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)