CVE-2026-32240

Name of the Vulnerable Software and Affected Versions Cap'n Proto versions prior to 1.4.0

Description Cap'n Proto is a data interchange format and capability-based RPC system. Prior to version 1.4.0, when using Transfer-Encoding: chunked, if a chunk's size was parsed to a value of 2^64 or larger, it would be truncated to a 64-bit integer. This could potentially enable HTTP request/response smuggling. The issue is related to the parsing of chunk sizes in HTTP requests when the Transfer-Encoding is set to chunked.

Recommendations Versions prior to 1.4.0 should be updated to version 1.4.0 or later.