Zapros, a Python HTTP client, prior to version 0.14.0 is vulnerable to denial of service via memory exhaustion. The issue affects all callers who streamed compressed responses relying on the chunk size — explicit (`iter_bytes(chunk_size=...)`) or the default — to bound memory. The decoder ignored that bound, so a chunk could be far larger than requested and a single compressed response could overflow memory. Version 0.14.0 contains a patch. Some workarounds are available. Read the still-compressed body with `Response.iter_raw()` / `Response.async_iter_raw()`, which bypass the built-in decoders, and decompress it yourself with an explicit output-size bound (e.g. `zlib`'s `max_length`), aborting once a configured limit is exceeded. Where feasible, send `Accept-Encoding: identity` to disable response compression so bodies are not decompressed client-side. Avoid decoding response bodies from untrusted servers.
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History
Mon, 21 Sep 2026 21:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Zapros, a Python HTTP client, prior to version 0.14.0 is vulnerable to denial of service via memory exhaustion. The issue affects all callers who streamed compressed responses relying on the chunk size — explicit (`iter_bytes(chunk_size=...)`) or the default — to bound memory. The decoder ignored that bound, so a chunk could be far larger than requested and a single compressed response could overflow memory. Version 0.14.0 contains a patch. Some workarounds are available. Read the still-compressed body with `Response.iter_raw()` / `Response.async_iter_raw()`, which bypass the built-in decoders, and decompress it yourself with an explicit output-size bound (e.g. `zlib`'s `max_length`), aborting once a configured limit is exceeded. Where feasible, send `Accept-Encoding: identity` to disable response compression so bodies are not decompressed client-side. Avoid decoding response bodies from untrusted servers. | |
| Title | Zapros: Streaming decoders ignored the requested chunk size, allowing a single compressed response chunk to allocate unbounded memory (decompression bomb) | |
| Weaknesses | CWE-770 | |
| References |
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| Metrics |
cvssV4_0
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-09-21T21:13:26.969Z
Reserved: 2026-07-10T18:25:21.466Z
Link: CVE-2026-61652
No data.
Status : Received
Published: 2026-09-21T22:16:57.680
Modified: 2026-09-21T22:16:57.680
Link: CVE-2026-61652
No data.
OpenCVE Enrichment
Updated: 2026-09-21T22:45:17Z
Weaknesses