CVSS 3.1
5.9 mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:HCVE-2026-126072 Action Pack: Possible DoS vulnerability in Action Controller Live streaming
Medium (5.9) in rails rails. EPSS 0.4% estimated probability of exploitation activity in the next 30 days. Fixed in actionpack 8.0.5.2, 8.1.4.1.
On this page
Action Pack is a framework for handling and responding to web requests. Prior to 8.1.4.1 and 8.0.5.2, ActionController::Live::Buffer#close pushes its end-of-stream marker onto the response's bounded queue while it holds the buffer's monitor. When the client has stopped reading and the queue is full, the push blocks, and Buffer#abort, which runs when the client disconnects or a write times out, waits indefinitely for the same monitor. Each such response could permanently hold a web server thread and its ActionController::Live thread, possibly resulting in a DoS vulnerability through thread exhaustion. Applications that stream responses with ActionController::Live, including send_stream, are affected. Applications that serve large files through Active Storage proxy mode are exposed to unauthenticated clients. This issue is fixed in versions 8.1.4.1 and 8.0.5.2.
Severity
- EPSS
- 0.4% estimated probability of exploitation activity in the next 30 days; 36th percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
- CISA's assessment (SSVC)
- Exploitation: none · Automatable: no · Technical impact: partial, assessed 2026-11-14. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
- CWE
- CWE-833 Deadlock
- Published
- Modified
- Assigned by
- GitHub_M (CNA)
- NVD analysis
- Awaiting analysis
- Record from
- the NVD, synced
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Affected
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| rails | >= 8.1, < 8.1.4.1 |
| rails | < 8.0.5.2 |
Fix and patched versions
actionpack(RubyGems): fixed in 8.1.4.1, 8.0.5.2
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-rwvh-fw6r-pwvp | RubyGems | actionpack | >=8.1.0.beta1 <8.1.4.1 | 8.1.4.1 |
| GHSA-rwvh-fw6r-pwvp | RubyGems | actionpack | <8.0.5.2 | 8.0.5.2 |
Linux distributions
| Distribution | Release | Package | Fixed in | Advisory |
|---|---|---|---|---|
| Debian | 12, 13, 14 | rails | no fix listed | DEBIAN-CVE-2026-126072 |
| Ubuntu | 24.04:LTS, 26.04:LTS, 26.10 and 4 more | rails | no fix listed | UBUNTU-CVE-2026-126072 |
From the distributions' data via OSV.dev: the Debian Security Tracker; Ubuntu Security Notices © Canonical Ltd., CC BY-SA 4.0. Modified: reformatted and linked to CVE records. Credits. On the distributions' own pages: Debian · Ubuntu.
Attack patterns (CAPEC)
- CAPEC-25 Forced Deadlock Likelihood: Low · Severity: High
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.
References
- https://github.com/rails/rails/commit/27ad18ed5900dee28ba20e9c6fc718ff751fa215
- https://github.com/rails/rails/commit/ccbfc09690fef05fdd2a9969c917a71b92cc98fc
- https://github.com/rails/rails/releases/tag/v8.0.5.2
- https://github.com/rails/rails/releases/tag/v8.1.4.1
- https://github.com/rails/rails/security/advisories/GHSA-rwvh-fw6r-pwvp