Quick answers
- Is CVE-2026-47073 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-47073 being exploited in the wild.
- How severe is CVE-2026-47073?
- High severity, with a CVSS score of 8.7, published 25 May 2026.
- Which products and versions are affected?
- Benoit Chesneau Hackney >= 2.0.0, < 4.0.1.
- Is there a fix for CVE-2026-47073?
- A patch was published on 2026-06-26. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-47073 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-47073?
- Check whether you run Benoit Chesneau Hackney at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The WebSocket client in `src/hackney_ws.erl` fails to impose upper bounds on memory consumption across three code paths: handshake response buffering, frame payload accumulation, and fragmentation buffering. In the handshake phase, `read_handshake_response/3` accumulates bytes indefinitely if the `\r\n\r\n` terminator is never sent. During frame parsing, `parse_payload/9` and `parse_active_payload/8` append incoming chunks to a buffer without validating the declared length against system limits. Finally, the `frag_buffer` can grow without bound if a server sends an endless stream of continuation frames without a final frame. An attacker-controlled WebSocket server can exploit these behaviors to cause an Out-Of-Memory (OOM) crash of the BEAM virtual machine. The vulnerability is patched in version 4.0.1.
Affected products
- benoitc hackney >= 2.0.0, < 4.0.1
Identifiers
- CVE-2026-47073
- GHSA-q8jg-fgj4-fphf
Timeline
- 2026-05-25: disclosed
- 2026-06-26: advisory: GitHub Advisory published
- 2026-06-26: patched