FKIE_CVE-2026-47066
Vulnerability from fkie_nvd - Published: 2026-05-25 15:16 - Updated: 2026-05-27 13:54
Severity
Summary
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.
References
| URL | Tags | ||
|---|---|---|---|
| 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | https://cna.erlef.org/cves/CVE-2026-47066.html | Third Party Advisory, Patch | |
| 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | https://github.com/benoitc/hackney/commit/e548aba1f97ffa3f4750da7b772998fb78c01894 | Patch | |
| 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | https://github.com/benoitc/hackney/security/advisories/GHSA-6cp8-v795-jr2j | Exploit, Vendor Advisory, Patch | |
| 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | https://osv.dev/vulnerability/EEF-CVE-2026-47066 | Third Party Advisory, Patch | |
| 134c704f-9b21-4f2e-91b3-4a467353bcc0 | https://github.com/benoitc/hackney/security/advisories/GHSA-6cp8-v795-jr2j | Exploit, Vendor Advisory, Patch |
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"descriptions": [
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"value": "Loop with Unreachable Exit Condition (\u0027Infinite Loop\u0027) 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.\n\nThe 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.\n\nThis issue affects hackney: from 2.0.0-beta.1 before 4.0.1."
}
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"id": "CVE-2026-47066",
"lastModified": "2026-05-27T13:54:47.413",
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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