Cap'n Proto is a data interchange format and capability-based RPC system. Prior to 1.4.0, a negative Content-Length value was converted to unsigned, treating it as an impossibly large length instead. In theory, this bug could enable HTTP request/response smuggling. This vulnerability is fixed in 1.4.0.
History

Sat, 14 Mar 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-681
References
Metrics threat_severity

None

cvssV3_1

{'score': 4.8, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N'}

threat_severity

Moderate


Fri, 13 Mar 2026 17:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 13 Mar 2026 10:00:00 +0000

Type Values Removed Values Added
First Time appeared Capnproto
Capnproto capnproto
Vendors & Products Capnproto
Capnproto capnproto

Thu, 12 Mar 2026 20:00:00 +0000

Type Values Removed Values Added
Description Cap'n Proto is a data interchange format and capability-based RPC system. Prior to 1.4.0, a negative Content-Length value was converted to unsigned, treating it as an impossibly large length instead. In theory, this bug could enable HTTP request/response smuggling. This vulnerability is fixed in 1.4.0.
Title Cap'n Proto has an integer overflow in KJ-HTTP
Weaknesses CWE-190
CWE-444
References
Metrics cvssV4_0

{'score': 6.3, 'vector': 'CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-03-12T19:33:25.052Z

Updated: 2026-03-13T16:15:03.051Z

Reserved: 2026-03-11T14:47:05.684Z

Link: CVE-2026-32239

cve-icon Vulnrichment

Updated: 2026-03-13T16:14:59.764Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-03-12T20:16:05.010

Modified: 2026-03-12T21:07:53.427

Link: CVE-2026-32239

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-03-12T19:33:25Z

Links: CVE-2026-32239 - Bugzilla