SpdyStream: DOS on CRI

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. An attacker can set `numSettings` to a value far exceeding the actual payload, triggering a large allocation before any setting data is read.   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. ## Impact  Any program that accepts SPDY connections using spdystream -- directly or through a dependent library -- is affected. A remote peer that can send SPDY frames to the service can crash the process with a single crafted SPDY control frame, causing denial of service. ## Affected versions  `github.com/moby/spdystream` <= v0.5.0 ## Fix  v0.5.1 addresses the receive-side allocation bugs and adds related hardening:   **Core fixes:**   - **SETTINGS entry-count validation** -- The SETTINGS frame reader now checks that `numSettings` is consistent with the declared frame length (`numSettings <= (length-4)/8`) before allocating.   - **Header count limit** -- `parseHeaderValueBlock` enforces a maximum number of headers per frame (default: 1000).   - **Header field size limit** -- Individual header name and value lengths are checked against a per-field size limit (default: 1 MiB) before allocation.   - **Connection closure on protocol error** -- The connection read loop now closes the underlying `net.Conn` when it encounters an `InvalidControlFrame` error, preventing further exploitation on the same connection.   **Additional hardening:**   - **Write-side bounds checks** -- All frame write methods now verify that payloads fit within the 24-bit length field, preventing the library from producing invalid frames.   **Configurable limits:**   - Callers can adjust the defaults using `NewConnectionWithOptions` or the lower-level `spdy.NewFramerWithOptions` with functional options: `WithMaxControlFramePayloadSize`, `WithMaxHeaderFieldSize`, and `WithMaxHeaderCount`.  

Source published

16 Apr 2026 20:44:01 UTC

Source modified

10 Sep 2026 03:51:02 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Publisher rating · HIGH