CVE-2026-91920 — Vulnerability intelligence
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Published:
- CVSS
- 6.5
- CISA KEV
- Not listed; not proof of no exploitation
Original source text (not a translation)
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.