CVE-2026-45728Public exploitNetwork attack vector

Source disclosure via forced single-file debug mode

Published May 26, 2026 · Updated May 26, 2026

Information disclosure in xyproto Algernon before 1.17.7 allows remote attackers to read server-side source through error responses. Single-file detection in MustServe forces debugMode on, and PrettyError embeds the absolute path, complete file bytes, and parser text in HTTP 200 responses. Exposure requires a reachable single-file Pongo2, Amber, or similar template deployment and an attacker-triggerable runtime error; bare Lua handlers alone do not reach this renderer.

CVSS severity7.5
High
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in xyproto Algernon before 1.17.7 allows remote attackers to read server-side source through error responses. Single-file detection in MustServe forces debugMode on, and PrettyError embeds the absolute path, complete file bytes, and parser text in HTTP 200 responses. Exposure requires a reachable single-file Pongo2, Amber, or similar template deployment and an attacker-triggerable runtime error; bare Lua handlers alone do not reach this renderer.

The record

CVE
CVE-2026-45728
Published
May 26, 2026
Updated
May 26, 2026
Vendor
xyproto
Product
Algernon
Classifications
CWE-209, CWE-489, CWE-540, CWE-1188, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 26, 2026CVE publishedPublication date reported by the CVE source.
  2. May 26, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.17.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

xyproto · Algernonversion=< 1.17.7

Published CVSS scores

7.5GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-209Generation of Error Message Containing Sensitive Information
CWE-489Active Debug Code
CWE-540Inclusion of Sensitive Information in Source Code
CWE-1188Initialization of a Resource with an Insecure Default
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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