CVE-2026-45728: xyproto algernon · Generation of Error Message Containing Sensitive Information
Affects xyproto algernonSource CVE Database V5
Not known to be exploited · CVSS 7.5 High : upgrade to 1.17.7 soon.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 22% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.17.7
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:NExploitation evidence
Disclosed: evidence found.
CVE published 26 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade algernon and github.com/xyproto/algernon to 1.17.7.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| xyprotoalgernon | Affected
| Fixed in
|
Gogithub.com/xyproto/algernonpkg:golang/github.com/xyproto/algernonOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade to Algernon version 1.17.7 or later, where this issue is fixed. Prior versions forcibly enable debug mode in single file mode causing sensitive information disclosure. No other official remediation or temporary fixes are documented. Patch status is not explicitly stated but the vendor fixed the issue in 1.17.7, so upgrading is the recommended action.
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.