High 8.7Published Aug 19, 2026

CVE-2026-52792Algernon: Server-side script source disclosure on Windows via NTFS filename

Updated under an hour ago (2026-10-19 08:23 UTC)

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Every CVE for xyproto algernon

Exploited in the last 30 days

Algernon is a small self-contained pure-Go web server. Prior to 1.17.9, Algernon on Windows selects a file handler in engine/handlers.go by calling filepath.Ext() without first rejecting NTFS-equivalent names such as x.lua::$DATA, x.lua., and x.lua . An unauthenticated client can append one of these suffixes to a public server-side script using the .lua, .tl, .po2, .amber, or .frm extension. The request path passes through URL2filename in utils/files.go, skips the renderer and execution cases, and reaches FilePage, os.Open, ReadAndLogErrors, and ToClient, while NTFS resolves the alias to the underlying script. The server consequently returns raw script source and can expose database credentials, API keys, and the SetCookieSecret value, which may permit forged session cookies. Linux and macOS hosts are not affected by this issue. This issue is fixed in version 1.17.9.

CVSS: 8.7 HIGH (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
Weakness (CWE): CWE-69
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: Aug 19, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

xyproto algernon xyproto:algernon (from the name)	before 1.17.9	CNA record

References

https://github.com/xyproto/algernon/security/advisories/GHSA-mm6c-5j6x-hq8mx-refsource-confirm
https://github.com/xyproto/algernon/commit/a6b0724928a0c35a29640b18ad5bd547f5e2efa6x-refsource-misc
https://github.com/xyproto/algernon/releases/tag/v1.17.9x-refsource-misc

The CVE record on cve.org NVD's entry

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.