Is there a public exploit for CVE-2026-126072?

No public exploit for CVE-2026-126072 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-126072?

CVE-2026-126072 scores CVSS 5.9 (v3.1), rated medium. EPSS puts the chance of exploitation in the next 30 days at 0.00411%.

What does CVE-2026-126072 affect?

CVE-2026-126072 affects actionpack.

5.9 Medium

Action Pack: Possible DoS vulnerability in Action Controller Live streaming

CVE-2026-126072

Impact 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 sendstream, are affected. Applications that serve large files through Active Storage proxy mode are exposed to unauthenticated clients. Releases The fixed releases are available at the normal locations. Patches for those who cannot upgrade at once: 8.1: https://github.com/rails/rails/commit/ccbfc09690fef05fdd2a9969c917a71b92cc98fc.patch 8.0: https://github.com/rails/rails/commit/27ad18ed5900dee28ba20e9c6fc718ff751fa215.patch Credit This issue was found by the Anthropic OSS Scanner (ANT-2026-LDFW5N2T).

Assessment

CVSS: 5.9 (v3.1)
Severity: Medium
EPSS: 0.00411% chance of exploitation in the next 30 days
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 12 November 2026
Last updated: 12 November 2026
Affected: actionpack
Weakness: CWE-833

CVSS vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

At the source

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