Description
Algernon is a small self-contained pure-Go web server. Prior to 1.17.7, the SSE event server's Access-Control-Allow-Origin response header was hardcoded to the wildcard * regardless of the caller's Origin. Because EventSource does not preflight and does not send cookies, the wildcard is sufficient to let any third-party page the developer visits open a cross-origin EventSource to the SSE port and read the live filename stream from JavaScript. This vulnerability is fixed in 1.17.7.
Details
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
Affected Packages
| Software | From version | Fixed in |
|---|---|---|
| github.com/xyproto/algernon | โ | โ |
| unknown | โ | โ |
References
Similar Threats
- Medium CVE-2026-46430
- Critical CVE-2026-45721
- Unknown GHSA-9v4j-7g44-qcqw
- High CVE-2026-45728
- Medium CVE-2025-65754
Exploit Protection
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