GHSA-w4f7-4cxr-rv3c

Source

https://github.com/advisories/GHSA-w4f7-4cxr-rv3c

Import Source

https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-w4f7-4cxr-rv3c/GHSA-w4f7-4cxr-rv3c.json

JSON Data

https://api.osv.dev/v1/vulns/GHSA-w4f7-4cxr-rv3c

Aliases

Published

2026-06-08T18:31:51Z

Modified

2026-07-29T16:11:36Z

Severity

6.3 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N CVSS Calculator

Summary

cowboy and gun affected by an HTTP Request/Response Splitting vulnerability

Details

Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting') vulnerability in ninenines cowlib allows HTTP response splitting via non-VCHAR bytes in structured-fields string values.

cow_http_struct_hd:escape_string/2 in cowlib only escapes \ and ", passing all other bytes through verbatim. This creates an encoder/decoder asymmetry: the matching parser accepts only printable ASCII (0x20–0x7E, excluding " and ), but the encoder emits any byte including CR and LF. An application that builds a structured HTTP header via cow_http_struct_hd:item/1 (or a higher-level wrapper such as cow_http_hd:wt_protocol/1) from attacker-controlled input can have \r\n injected into the serialized header value. Once on the wire, the injected CRLF terminates the current header and any following bytes are interpreted as a new header, enabling HTTP response splitting.

This issue affects cowlib from 2.9.0.

Database specific

{
    "cwe_ids": [
        "CWE-113"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-29T15:48:39Z",
    "nvd_published_at": "2026-06-08T17:16:43Z",
    "severity": "MODERATE"
}

References

Affected packages

Hex / cowboy

Package

Name: cowboy
Purl: pkg:hex/cowboy

Affected ranges

Type: SEMVER
Events: Introduced

0 Unknown introduced version / All previous versions are affected

Fixed

2.16.0

Affected versions

1.*

1.0.0

1.0.1

1.0.2

1.0.3

1.0.4

1.1.0

1.1.1

1.1.2

2.*

2.0.0

2.1.0

2.2.0

2.2.1

2.2.2

2.3.0

2.4.0

2.5.0

2.6.0

2.6.1

2.6.2

2.6.3

2.7.0

2.8.0

2.9.0

2.10.0

2.11.0

2.12.0

2.13.0

2.14.0

2.14.1

2.14.2

2.15.0

Database specific

source

"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-w4f7-4cxr-rv3c/GHSA-w4f7-4cxr-rv3c.json"

Hex / gun

Package

Name: gun
Purl: pkg:hex/gun

Affected ranges

Type: SEMVER
Events: Introduced

0 Unknown introduced version / All previous versions are affected

Fixed

2.16.0

Affected versions

1.*

1.0.0-pre.1

1.0.0-pre.2

1.0.0-pre.4

1.0.0-pre.5

1.0.0-pre.4b

1.0.0

1.1.0

1.2.0

1.3.0

1.3.1

1.3.2

1.3.3

2.*

2.0.0-rc.1

2.0.0-rc.2