CVE-2026-46430

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

MEDIUM
4.3
CVSS Score
Published: May 26, 2026 at 04:41 PM UTC
Updated: July 24, 2026 at 11:23 AM UTC
1 product affected across 1 vendorAlgernon

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Severity
MEDIUM4.3
Exploit prediction
EPSS 0.2%
SSVC
PoC

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.17.7
Affected range stops below 1.17.7, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (1)

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

4.3MEDIUMGitHub_M
Attack Vector
ADJACENT_NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-668CWE-1188

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