CVE-2026-46431 - Algernon: Auto-refresh SSE event server sets Access-Control-Allow-Origin: *
CVE ID :CVE-2026-46431
Published : May 26, 2026, 4:42 p.m. | 18 minutes ago
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.
Severity: 0.0 | NA
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Published : May 26, 2026, 4:42 p.m. | 18 minutes ago
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.
Severity: 0.0 | NA
Visit the link for more details, such as CVSS details, affected products, timeline, and more...