CVE-2026-46431
MEDIUM EPSS 12.3%
Published May 26, 20261mo ago · Modified Jun 17, 20262w ago
4.3 CVSS 3.1
Published May 26, 2026 1mo ago
Last Modified Jun 17, 2026 2w 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.
CVSS Details
Base Score
Exploitability
Impact
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction Required
Scope Unchanged
Confidentiality Low
Integrity None
Availability None
Threat Intelligence
EPSS Exploit Probability
12.3% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available
Weaknesses 1
CWE-942
References 1
- github.com https://github.com/xyproto/algernon/security/advisories/GHSA-hw27-4v2q-5qff
Remediation
No remediation data recorded yet
Check vendor advisories and the NVD entry for patch availability.