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USN-8650-1: Cap'n Proto vulnerabilities

USN-8650-1: Cap'n Proto vulnerabilities

Ubuntu • August 19, 2026

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 or response smuggling. ( CVE-2026-32239 , CVE-2026-32240 )

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 or response smuggling. ( CVE-2026-32239 , CVE-2026-32240 )

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 or response smuggling. ( CVE-2026-32239 , CVE-2026-32240 )

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 or response smuggling. ( CVE-2026-32239 , CVE-2026-32240 )

In general, a standard system update will make all the necessary changes.

The problem can be corrected by updating your system to the following package versions:

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