CVE-2026-46431: Algernon: Auto-refresh SSE event server sets Access-Control-Allow-Origin: *
xyproto · algernon
Affected: xyproto algernon · Exploitation: unlikely (under 1%)
Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.
Higher than 12% of scored CVEs
DescriptionCVE.org
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.
Affected products1
From the CVE record. A product or version that is not listed is unknown, not unaffected.
- xyproto · algernon< 1.17.7
On the Atlas
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CoverageNo articles yet
No CyberSIXT article names CVE-2026-46431 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.