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Medium 4.3Published May 26, 2026

CVE-2026-46430Algernon: Auto-refresh SSE event server binds to all interfaces by default on Linux/macOS

Updated under an hour ago ()

Does this affect you?

It affects xyproto algernon. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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.

CVSS
4.3 MEDIUM (v3.1, CNA)CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Weakness (CWE)
CWE-668, CWE-1188
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
GitHub_M
NVD analysis
Deferred
Record last updated
May 26, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
xyproto algernon
xyproto:algernon (from the name)
before 1.17.7
CNA record

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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