CVE-2026-45728

Algernon: Single-file mode unconditionally enables debug mode

HIGH
7.5
CVSS Score
Published: May 26, 2026 at 04:38 PM UTC
Updated: July 24, 2026 at 11:23 AM UTC
1 product affected across 1 vendorAlgernon

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Severity
HIGH7.5
Exploit prediction
EPSS 0.3%
SSVC
PoC

Description

Algernon is a small self-contained pure-Go web server. Prior to 1.17.7, when Algernon is invoked with a single file path instead of a directory, singleFileMode is set to true and debugMode is forcibly enabled. debugMode activates the PrettyError renderer, which on any Lua or template error response dumps the absolute path of the file that errored, complete byte contents of that file, and exception or parser error text. This response is served with HTTP 200 OK to whoever sent the request that triggered the error. Any client able to reach the server and able to provoke a runtime error in the served script obtains the full server-side source of that script and of any sibling Lua data file consulted during the request. This vulnerability is fixed in 1.17.7.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.17.7
Affected range stops below 1.17.7, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (1)

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-209CWE-489CWE-540CWE-1188

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