CVE-2026-47077
Unbounded body accumulation in HTTP/3 response loop in hackney
Description
Allocation of Resources Without Limits or Throttling vulnerability in benoitc hackney allows Flooding. hackney_h3:await_response_loop/6 accumulates the HTTP/3 response body in memory without any size cap. The after Timeout clause is a per-message inactivity timer that resets on every received chunk, housekeeping message, or settings frame — it is not a wall-clock deadline. A malicious HTTP/3 server that emits one small chunk every Timeout - 1 ms with Fin = false and never sends a final frame keeps the loop alive indefinitely while the accumulation buffer grows linearly without bound, eventually exhausting the BEAM process heap and causing an out-of-memory condition. This issue affects hackney: from 2.0.0 before 4.0.1.
INFO
Published Date :
May 25, 2026, 3:16 p.m.
Last Modified :
May 27, 2026, 1:53 p.m.
Remotely Exploit :
Yes !
Source :
6b3ad84c-e1a6-4bf7-a703-f496b71e49db
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 4.0 | HIGH | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | ||||
| CVSS 4.0 | HIGH | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db |
Solution
- Update hackney to version 4.0.1 or later.
- Implement size caps for response bodies.
- Configure appropriate inactivity timers.
- Monitor resource usage.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-47077.
| URL | Resource |
|---|---|
| https://cna.erlef.org/cves/CVE-2026-47077.html | Third Party Advisory Patch |
| https://github.com/benoitc/hackney/commit/3d25f9fea26c90609de9d64366fedfe5065413bc | Patch |
| https://github.com/benoitc/hackney/security/advisories/GHSA-jq4m-q6p2-8gwc | Exploit Vendor Advisory Patch |
| https://osv.dev/vulnerability/EEF-CVE-2026-47077 | Third Party Advisory Patch |
| https://github.com/benoitc/hackney/security/advisories/GHSA-jq4m-q6p2-8gwc | Exploit Vendor Advisory Patch |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-47077 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-47077
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-47077 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-47077 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
May. 27, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added CPE Configuration OR *cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:* versions from (including) 2.0.0 up to (excluding) 4.0.1 Added Reference Type EEF: https://cna.erlef.org/cves/CVE-2026-47077.html Types: Patch, Third Party Advisory Added Reference Type EEF: https://github.com/benoitc/hackney/commit/3d25f9fea26c90609de9d64366fedfe5065413bc Types: Patch Added Reference Type CISA-ADP: https://github.com/benoitc/hackney/security/advisories/GHSA-jq4m-q6p2-8gwc Types: Exploit, Patch, Vendor Advisory Added Reference Type EEF: https://github.com/benoitc/hackney/security/advisories/GHSA-jq4m-q6p2-8gwc Types: Exploit, Patch, Vendor Advisory Added Reference Type EEF: https://osv.dev/vulnerability/EEF-CVE-2026-47077 Types: Patch, Third Party Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
May. 26, 2026
Action Type Old Value New Value Added Reference https://github.com/benoitc/hackney/security/advisories/GHSA-jq4m-q6p2-8gwc -
New CVE Received by 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
May. 25, 2026
Action Type Old Value New Value Added Description Allocation of Resources Without Limits or Throttling vulnerability in benoitc hackney allows Flooding. hackney_h3:await_response_loop/6 accumulates the HTTP/3 response body in memory without any size cap. The after Timeout clause is a per-message inactivity timer that resets on every received chunk, housekeeping message, or settings frame — it is not a wall-clock deadline. A malicious HTTP/3 server that emits one small chunk every Timeout - 1 ms with Fin = false and never sends a final frame keeps the loop alive indefinitely while the accumulation buffer grows linearly without bound, eventually exhausting the BEAM process heap and causing an out-of-memory condition. This issue affects hackney: from 2.0.0 before 4.0.1. Added CVSS V4.0 AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-400 Added Reference https://cna.erlef.org/cves/CVE-2026-47077.html Added Reference https://github.com/benoitc/hackney/commit/3d25f9fea26c90609de9d64366fedfe5065413bc Added Reference https://github.com/benoitc/hackney/security/advisories/GHSA-jq4m-q6p2-8gwc Added Reference https://osv.dev/vulnerability/EEF-CVE-2026-47077