CVE-2026-47066

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Source

https://cve.org/CVERecord?id=CVE-2026-47066

Import Source

https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-47066.json

JSON Data

https://api.osv.dev/v1/vulns/CVE-2026-47066

Aliases

Published

2026-05-25T14:00:39.707Z

Modified

2026-07-08T08:13:38.633947345Z

Severity

8.7 (High) CVSS_V4 - 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 CVSS Calculator

Summary

Infinite loop in Alt-Svc header parser in hackney

Details

Loop with Unreachable Exit Condition ('Infinite Loop') vulnerability in benoitc hackney allows Excessive Allocation. The Alt-Svc response header parser in src/hackneyaltsvc.erl does not guarantee forward progress. When parsetoken/2 receives a non-token, non-whitespace, non-comma byte (e.g. !, @, =, ;), it returns the input unchanged. skipcomma/1 also returns the buffer unchanged when the first byte is not a comma. parseentries/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 parseandcache/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.

Database specific

{
    "unresolved_ranges": [
        {
            "source": "AFFECTED_FIELD",
            "extracted_events": [
                {
                    "introduced": "408e5fe20302226ea8c74dde2bcbd452d712b5b2"
                },
                {
                    "fixed": "e548aba1f97ffa3f4750da7b772998fb78c01894"
                }
            ]
        }
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47066.json",
    "cna_assigner": "EEF",
    "cwe_ids": [
        "CWE-835"
    ]
}

References

Affected packages

Git / github.com/benoitc/hackney

Affected ranges

Type

GIT

Repo

https://github.com/benoitc/hackney

Events

Introduced

a7ce34b42892ab305b2ef7dbe873bcabf4ef93ca

Fixed

c41c8d48ace8141b003f6f1de3ca6734a0c53056

Fixed

e548aba1f97ffa3f4750da7b772998fb78c01894

Database specific

{
    "source": [
        "CPE_RANGE",
        "REFERENCES"
    ],
    "cpe": "cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*",
    "extracted_events": [
        {
            "introduced": "2.0.0"
        },
        {
            "fixed": "4.0.1"
        }
    ]
}

Affected versions

2.*

2.0.0

2.0.1

3.*

3.0.1

3.0.2

3.0.3

3.1.0

3.1.1

3.1.2

3.2.0

3.2.1

4.*

4.0.0

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-47066.json"