CVE-2026-55562: XSS (CVSS 9)

Description

Cronicle is a multi-server task scheduler and runner, with a web based front-end UI. Prior to 0.9.119, the administrator Activity Log in htdocs/js/pages/admin/Activity.js concatenates the attacker-controlled item.user.full_name value into HTML without applying encode_entities and inserts the result through this.div.html. The bundled pixl-server-user input filter can be bypassed by a tag containing a line break because its regular expression does not match newlines. An authenticated non-administrator can update the attacker's own name through /api/user/update using a valid session and current password; when free_accounts is enabled, an anonymous attacker can instead plant the name during self-registration. The stored name executes script in an administrator's session when the Activity Log is opened, enabling administrator takeover and subsequent command execution through privileged Cronicle features. This issue is fixed in version 0.9.119.

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CVSS v3.1 Score

9.0

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0037

Probability of exploitation

0.29%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

References

Other References

https://github.com/jhuckaby/Cronicle/commit/8b60eb5b041614ab661df50e58e612f5e42a7d30 https://github.com/jhuckaby/Cronicle/releases/tag/v0.9.119 https://github.com/jhuckaby/Cronicle/security/advisories/GHSA-vh39-3pcm-2j63 https://github.com/jhuckaby/Cronicle/security/advisories/GHSA-vh39-3pcm-2j63

Frequently Asked Questions

What is CVE-2026-55562? +

Cronicle is a multi-server task scheduler and runner, with a web based front-end UI. Prior to 0.9.119, the administrator Activity Log in htdocs/js/pages/admin/Activity.js concatenates the attacker-controlled item.user.full_name value into HTML without applying encode_entities and inserts the result through this.div.html. The bundled pixl-server-user input filter can be bypassed by a tag containing a line break because its regular expression does not match newlines. An authenticated non-administrator can update the attacker's own name through /api/user/update using a valid session and current password; when free_accounts is enabled, an anonymous attacker can instead plant the name during self-registration. The stored name executes script in an administrator's session when the Activity Log is opened, enabling administrator takeover and subsequent command execution through privileged Cronicle features. This issue is fixed in version 0.9.119. It has a CVSS v3.1 base score of 9.0 (CRITICAL).

How severe is CVE-2026-55562? +

CVE-2026-55562 has a CVSS v3.1 score of 9.0 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0037, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-55562? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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