CVE-2026-91920

MEDIUM

MEDIUM Priority: 0.00 BB Relevance: 73/100

Published: 2026-10-30 Modified: 2026-10-30 First seen: 2026-10-30 Status: active

Attack Surface

Network Low Complexity No Auth No Interaction

CVSS Vector Breakdown

AV: Network

AC: Low

PR: None

UI: None

S: Unchanged

C: None

I: Low

A: Low

Description

A flaw was found in the ChunkReader component of the Undertow web server, which is used to handle chunked transfer encoding in HTTP requests. The issue occurs because a security check for the chunk size is performed before the value is shifted, allowing a specifically crafted 15-digit chunk size to bypass the limit and overflow into internal state flags. This can cause the server to terminate a request body prematurely and interpret the remaining data as a separate, smuggled request.