CVE-2026-52792

HIGHCVSS 8.7/10EPSS 0.43%

Last modified

CVE-2026-52792 is a high-severity vulnerability rated 8.7/10 on the CVSS scale. 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 . EPSS estimates a 0.43% chance of exploitation in the next 30 days.

Description

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.

Metrics

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
xyprotoalgernon< 1.17.9

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is CVE-2026-52792?
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.
How severe is CVE-2026-52792?
CVE-2026-52792 has a CVSS score of 8.7/10 (HIGH severity). The EPSS model estimates a 0.43% probability of exploitation in the next 30 days.
How do I fix CVE-2026-52792?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST