MEDIUM · 6.5

CVE-2026-32239

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. ...

Vulnerability 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.

CVSS Score

6.5

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE

Affected Products

VendorProductVersions
CapnprotoCapnproto< 1.4.0

Related Weaknesses (CWE)

References

FAQ

What is CVE-2026-32239?

CVE-2026-32239 is a vulnerability with a CVSS score of 6.5 (MEDIUM). 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. ...

How severe is CVE-2026-32239?

CVE-2026-32239 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-32239?

Check the references section above for vendor advisories and patch information. Affected products include: Capnproto Capnproto.