CVE-2026-47073: benoitc hackney · Uncontrolled Resource Consumption
Affects benoitc hackneySource CVE Database V5
Not known to be exploited · CVSS 8.7 High : upgrade to 4.0.1 soon.
Data as of 26 Oct 2026, 09:16 UTC
- EPSS
- 0.8% chance of exploitation in 30 days – higher than 58% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 4.0.1, ce0109e2970ace6e20ff29bae9d05c3ac22ec6dc
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 25 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade hackney and benoitc/hackney to 4.0.1; hackney to ce0109e2970ace6e20ff29bae9d05c3ac22ec6dc.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| benoitchackney | Affected
| Fixed in
|
| benoitchackney | Affected
| Fixed in
|
GitHubbenoitc/hackneypkg:github/benoitc/hackneyOther threats | Affected
| Fixed in
|
Hexhackneypkg:hex/hackneyOther threats | Affected
| Fixed in
|
CPE configurations (1)
cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
If you cannot patch yet, users should consider limiting exposure to untrusted WebSocket servers or implementing external controls to detect and block malicious WebSocket traffic.
Description
Allocation of Resources Without Limits or Throttling vulnerability in benoitc hackney allows Flooding. The WebSocket client in src/hackney_ws.erl imposes no upper bound on memory consumption in three code paths. First, read_handshake_response/3 accumulates received bytes into a growing buffer with no size cap; the per-receive timeout resets on every chunk, so a server that streams bytes without ever sending \r\n\r\n causes the buffer to grow until memory is exhausted. Second, parse_payload/9 and parse_active_payload/8 do not validate the declared frame payload length against any limit; because RFC 6455 allows payload lengths up to 2^63-1 bytes, a server that announces a very large frame and dribbles bytes causes the accumulation buffer to grow until OOM. Third, the frag_buffer field in #ws_data{} accumulates continuation frames indefinitely; a server that sends an endless stream of non-final (nofin) fragmented frames without ever sending a final (fin) frame grows frag_buffer without bound. In all three cases the attacker only needs to control the WebSocket server the hackney client connects to, with no authentication or special client configuration required. This issue affects hackney: from 2.0.0 before 4.0.1.
References
- github.com/benoitc/hackney/security/advisories/GHSA-q8jg-fgj4-fphf (opens in a new tab)
- cna.erlef.org/cves/CVE-2026-47073.html (opens in a new tab)
- osv.dev/vulnerability/EEF-CVE-2026-47073 (opens in a new tab)
- github.com/benoitc/hackney/commit/ce0109e2970ace6e20ff29bae9d05c3ac22ec6dc (opens in a new tab)