CVE-2026-47067
Atom table exhaustion via unrecognized URL schemes in hackney
- State
- Published
- Severity
- 8.7 High
- Published
- May 25, 2026
- Updated
- May 27, 2026
- Reserved
- May 18, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.7 High | 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 | EEF |
Weaknesses
- CWE-770 Allocation of Resources Without Limits or Throttling
Affected Products
| Product | Versions |
|---|---|
hackneybenoitc |
|
hackneybenoitc |
|
References
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