CVE-2026-45728
Algernon: Single-file mode unconditionally enables debug mode
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
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.
Public exploit
A reference of the record is tagged as an exploit or proof of concept: anyone can try it against an unpatched system. CISA's SSVC rates its exploitation: a proof of concept is public.
- https://github.com/xyproto/algernon/security/advisories/GHSA-fwqx-8365-9983 (opens in a new tab)x_refsource_CONFIRMexploit
Timeline
ID reserved
By GitHub_M
- 13 days later
· 13 days later
Published
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N |
| NVDNVD · Deferred | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N |
- EPSS (exploitation in 30 days)
- 0.30% · top 77% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Weakness
- CWE-209: Generation of Error Message Containing Sensitive Information (opens in a new tab)All about CWE-209 and its CVEs
- CWE-489: Active Debug Code (opens in a new tab)All about CWE-489 and its CVEs
- CWE-540: Inclusion of Sensitive Information in Source Code (opens in a new tab)All about CWE-540 and its CVEs
- CWE-1188: Insecure Default Initialization of Resource (opens in a new tab)All about CWE-1188 and its CVEs
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- Gogithub.com/xyproto/algernonGHSA-fwqx-8365-9983 (opens in a new tab)
References (1)
- https://github.com/xyproto/algernon/security/advisories/GHSA-fwqx-8365-9983 (opens in a new tab)x_refsource_CONFIRMexploit
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-fwqx-8365-9983 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-45728)Record last updated .