GO-2026-4958

Summary

Uncontrolled resource consumption when parsing SPDY frames in github.com/moby/spdystream

Description

The SPDY/3 frame parser in spdystream does not validate attacker-controlled counts and lengths before allocating memory. A remote peer that can send SPDY frames to a service using spdystream can cause the process to allocate gigabytes of memory with a small number of malformed control frames, leading to an out-of-memory crash.

Three allocation paths in the receive side are affected:

1. SETTINGS entry count: The SETTINGS frame reader reads a 32-bit numSettings from the payload and allocates a slice of that size without checking it against the declared frame length.
2. Header count: parseHeaderValueBlock reads a 32-bit numHeaders from the decompressed header block and allocates an http.Header map of that size with no upper bound.
3. Header field size: Individual header name and value lengths are read as 32-bit integers and used directly as allocation sizes with no validation.

Because SPDY header blocks are zlib-compressed, a small on-the-wire payload can decompress into attacker-controlled bytes that the parser interprets as 32-bit counts and lengths. A single crafted frame is enough to exhaust process memory.