CVE-2026-29779
Published: 07 March 2026
Summary
CVE-2026-29779 is a high-severity Exposure of Sensitive Information to an Unauthorized Actor (CWE-200) vulnerability in Lyc8503 Uptimeflare. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Credentials In Files (T1552.001); ranked at the 13.5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 AC-22 (Publicly Accessible Content) and SI-2 (Flaw Remediation).
Deeper analysis
CVE-2026-29779 affects UptimeFlare, a serverless uptime monitoring and status page solution powered by Cloudflare Workers. Prior to commit 377a596, the configuration file uptime.config.ts exported both pageConfig, which is safe for client-side use, and workerConfig, which contains sensitive server-only data, from the same module. The pages/incidents.tsx file imported and used workerConfig directly within client-side component code, resulting in the entire workerConfig object being bundled into the client-side JavaScript served to all visitors. This vulnerability, classified under CWE-200 (Exposure of Sensitive Information), carries a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N).
Any unauthenticated visitor to an affected UptimeFlare deployment can exploit this vulnerability with low complexity over the network and without user interaction. By simply loading the incidents page or related client-side resources, attackers gain access to the sensitive data within the workerConfig object embedded in the JavaScript bundle, enabling high-impact confidentiality breaches such as exposure of configuration secrets.
The issue has been patched in commit 377a596, as detailed in the GitHub security advisory GHSA-36q9-v7p3-vj6v, issue #198, and the commit itself. Security practitioners should ensure deployments are updated to this commit or later to mitigate exposure of workerConfig data.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-10152
Vulnerability details
UptimeFlare is a serverless uptime monitoring & status page solution, powered by Cloudflare Workers. Prior to commit 377a596, configuration file uptime.config.ts exports both pageConfig (safe for client use) and workerConfig (server-only, contains sensitive data) from the same module. Due to…
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pages/incidents.tsx importing and using workerConfig directly inside client-side component code, the entire workerConfig object was included in the client-side JavaScript bundle served to all visitors. This issue has been patched via commit 377a596.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Vulnerability directly exposes workerConfig secrets (incl. credentials/tokens) inside publicly served client-side JS bundles, enabling collection of unsecured credentials from files without server compromise.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly restricts sensitive workerConfig data from being included in publicly accessible client-side JavaScript bundles served to unauthenticated visitors.
Requires timely remediation of the specific flaw exposing workerConfig in client bundles, as implemented via patch commit 377a596.
Filters sensitive information from output such as the incidents page JavaScript bundle prior to serving to external unauthenticated users.