CHUNK-SIZE-PLUS

Test IDSMUG-CHUNK-SIZE-PLUS
CategorySmuggling
RFCRFC 9112 §7.1
RequirementImplicit MUST (grammar violation)
Expected400 or close

What it sends

A chunked request where chunk-size is prefixed by +.

POST / HTTP/1.1\r\n
Host: localhost:8080\r\n
Transfer-Encoding: chunked\r\n
\r\n
+5\r\n
hello\r\n
0\r\n
\r\n

What the RFC says

“chunk-size = 1*HEXDIG” – RFC 9112 Section 7.1

The plus sign is not a hexadecimal digit. The chunk-size token is invalid.

Why it matters

Lenient numeric parsing (+5) in one component and strict parsing in another creates parser disagreement and desync opportunities.

Sources