CVE-2026-46430

Algernon: Auto-refresh SSE event server binds to all interfaces by default on Linux/macOS

Published May 26, 2026 CVSS 3.1 · 4.3 Medium EPSS < 1% KEV · Not listed
Description
Algernon is a small self-contained pure-Go web server. Prior to 1.17.7, the SSE event server bound to 0.0.0.0:5553 on Linux/macOS by default because the platform-dependent host default in engine/flags.go:39-46 set host = "" for non-Windows, and utils.JoinHostPort("", ":5553") resolves to ":5553". This vulnerability is fixed in 1.17.7.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-gj84-924c-48fx Algernon: Auto-refresh SSE event server binds to all interfaces by default on Linux/macOS
History
Type Values Removed Values Added
First Time appeared Xyproto
Xyproto algernon
Vendors & Products Xyproto
Xyproto algernon
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Algernon is a small self-contained pure-Go web server. Prior to 1.17.7, the SSE event server bound to 0.0.0.0:5553 on Linux/macOS by default because the platform-dependent host default in engine/flags.go:39-46 set host = "" for non-Windows, and utils.JoinHostPort("", ":5553") resolves to ":5553". This vulnerability is fixed in 1.17.7.
Title Algernon: Auto-refresh SSE event server binds to all interfaces by default on Linux/macOS
Weaknesses CWE-1188
CWE-668
References
Metrics cvssV3_1

{'score': 4.3, 'vector': 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
May 26, 2026, 6:57 PM
Reserved
May 13, 2026, 10:18 PM
Status
Deferred
Published
May 26, 2026, 5:16 PM
Modified
Jul 24, 2026, 11:10 AM