USN-8650-1: Cap'n Proto vulnerabilities

Chanho Kim and Jihyeok Han discovered that Cap'n Proto incorrectly handled negative Content-Length values or excessively large chunk sizes when processing HTTP messages. An attacker could possibly use these issues to cause HTTP messages to be interpreted inconsistently, resulting in HTTP request ...

JLSEC-2026-1268 Cap'n Proto and its Rust implementation vulnerable to out-of-bounds read due to logic error handling list-of-list

The Cap'n Proto library and capnp Rust package are vulnerable to out-of-bounds read due to logic error handling list-of-list. If a message consumer expects data of type "list of pointers", and if the consumer performs certain specific actions on such data, then a message producer can cause the...

JLSEC-2026-1269

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...

JLSEC-2026-1270

Cap'n Proto is a data interchange format and capability-based RPC system. Prior to 1.4.0, when using Transfer-Encoding: chunked, if a chunk's size parsed to a value of 2^64 or larger, it would be truncated to a 64-bit integer. In theory, this bug could enable HTTP request/response smuggling. This...

SUSE 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. In theory, this bug could enable HTTP request/response smuggling. This vulnerability is fixed in...

Linux Distros Unpatched Vulnerability : CVE-2026-32239

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - 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...

Linux Distros Unpatched Vulnerability : CVE-2026-32240

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - Cap'n Proto is a data interchange format and capability-based RPC system. Prior to 1.4.0, when using Transfer-Encoding: chunked, if a chunk's size parsed to a...

DEBIAN-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. In theory, this bug could enable HTTP request/response smuggling. This vulnerability is fixed in...

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. In theory, this bug could enable HTTP request/response smuggling. This vulnerability is fixed in...

CVE-2026-32240

Cap'n Proto is a data interchange format and capability-based RPC system. Prior to 1.4.0, when using Transfer-Encoding: chunked, if a chunk's size parsed to a value of 2^64 or larger, it would be truncated to a 64-bit integer. In theory, this bug could enable HTTP request/response smuggling. This...

UBUNTU-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. In theory, this bug could enable HTTP request/response smuggling. This vulnerability is fixed in...

CVE-2026-32240

Cap'n Proto is a data interchange format and capability-based RPC system. Prior to 1.4.0, when using Transfer-Encoding: chunked, if a chunk's size parsed to a value of 2^64 or larger, it would be truncated to a 64-bit integer. In theory, this bug could enable HTTP request/response smuggling. This...

CVE-2026-32240 Cap'n Proto: Integer overflow in KJ-HTTP chunk size

Cap'n Proto is a data interchange format and capability-based RPC system. Prior to 1.4.0, when using Transfer-Encoding: chunked, if a chunk's size parsed to a value of 2^64 or larger, it would be truncated to a 64-bit integer. In theory, this bug could enable HTTP request/response smuggling. This...

CVE-2026-32240

Cap'n Proto prior to 1.4.0 has a vulnerability where, with Transfer-Encoding: chunked, a chunk size parsed to >= 2^64 would be truncated to 64 bits, potentially enabling HTTP request/response smuggling. The issue affects Cap'n Proto’s chunked transfer handling and is fixed in 1.4.0. According ...

CVE-2026-32240 Cap'n Proto: Integer overflow in KJ-HTTP chunk size

Cap'n Proto is a data interchange format and capability-based RPC system. Prior to 1.4.0, when using Transfer-Encoding: chunked, if a chunk's size parsed to a value of 2^64 or larger, it would be truncated to a 64-bit integer. In theory, this bug could enable HTTP request/response smuggling. This...

EUVD-2026-11688

Cap'n Proto is a data interchange format and capability-based RPC system. Prior to 1.4.0, when using Transfer-Encoding: chunked, if a chunk's size parsed to a value of 2^64 or larger, it would be truncated to a 64-bit integer. In theory, this bug could enable HTTP request/response smuggling. This...

CVE-2026-32240 Cap'n Proto: Integer overflow in KJ-HTTP chunk size

Cap'n Proto is a data interchange format and capability-based RPC system. Prior to 1.4.0, when using Transfer-Encoding: chunked, if a chunk's size parsed to a value of 2^64 or larger, it would be truncated to a 64-bit integer. In theory, this bug could enable HTTP request/response smuggling. This...

CVE-2026-32239 Cap'n Proto has an integer overflow in KJ-HTTP

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...

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. In theory, this bug could enable HTTP request/response smuggling. This vulnerability is fixed in...

CVE-2026-32239

Cap'n Proto prior to 1.4.0 mishandles a negative Content-Length value by converting it to unsigned, effectively allowing an HTTP request/response smuggling vector. The issue affects Cap'n Proto’s data interchange/RPC handling where untrusted HTTP boundaries could be exploited. The vulnerability i...