Description
Allocation of Resources Without Limits or Throttling vulnerability in benoitc hackney allows Flooding. The URL parser in src/hackney_url.erl converts every unrecognized URL scheme to a permanent BEAM atom via binary_to_atom/2. BEAM atoms are never garbage-collected and the atom table defaults to a hard limit of 1,048,576 entries. An attacker who can supply URLs with attacker-chosen scheme prefixes — directly as request targets, as configured webhook URLs, or via Location headers followed during redirects — can exhaust the atom table and crash the entire BEAM VM with system_limit. This issue affects hackney: from 2.0.0 before 4.0.1.
Problem types
CWE-770 Allocation of Resources Without Limits or Throttling
Product status
2.0.0 (semver) before 4.0.1
d9713695c0d99855d12c73fd8a0b4be0543950c4 (git) before 31f6f0e27e096ad88743dfded4f030a3ee74972e
Credits
Peter Ullrich
Benoit Chesneau
Jonatan Männchen / EEF
References
github.com/...ackney/security/advisories/GHSA-9653-rcfr-5c62
github.com/...ackney/security/advisories/GHSA-9653-rcfr-5c62
cna.erlef.org/cves/CVE-2026-47067.html
osv.dev/vulnerability/EEF-CVE-2026-47067
github.com/...ommit/31f6f0e27e096ad88743dfded4f030a3ee74972e