CVE-2026-47066

7.5 HIGH
Published: May 25, 2026 Modified: May 27, 2026
View on NVD

Description

Loop with Unreachable Exit Condition ('Infinite Loop') vulnerability in benoitc hackney allows Excessive Allocation. The Alt-Svc response header parser in src/hackney_altsvc.erl does not guarantee forward progress. When parse_token/2 receives a non-token, non-whitespace, non-comma byte (e.g. !, @, =, ;), it returns the input unchanged. skip_comma/1 also returns the buffer unchanged when the first byte is not a comma. parse_entries/2 then recurses with identical data, creating a tight infinite tail-recursive loop that pins a scheduler at 100% CPU. The calling process never returns. The entry point parse_and_cache/3 is called synchronously in the connection process on every HTTP response. A single-byte Alt-Svc: ! response header is sufficient to trigger the hang; the header is fully controlled by any HTTP origin the client connects to. This issue affects hackney: from 2.0.0-beta.1 before 4.0.1.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://cna.erlef.org/cves/CVE-2026-47066.html
Source: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Third Party Advisory Patch
https://github.com/benoitc/hackney/security/advisories/GHSA-6cp8-v795-jr2j
Source: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Exploit Vendor Advisory Patch
https://osv.dev/vulnerability/EEF-CVE-2026-47066
Source: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Third Party Advisory Patch
https://github.com/benoitc/hackney/security/advisories/GHSA-6cp8-v795-jr2j
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
Exploit Vendor Advisory Patch

5 reference(s) from NVD

Quick Stats

CVSS v3 Score
7.5 / 10.0
EPSS (Exploit Probability)
0.7%
47th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

benoitc