CVE-2026-62979
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AI Threat Summary
CVE-2026-62979 is a moderate vulnerability affecting the target software. Threat hunters should monitor for exploit attempts and apply vendor patches immediately.
Description
jack lets users share media libraries through their Radarr/Sonarr stack, peer-to-peer. Prior to 0.1.0, `middleware/handle-error.ts` serializes raw `FetchError` objects into HTTP responses. `lib/servers/base.ts` attaches outbound request headers on upstream non-success responses and schema-validation failures; the public `extras` field in `lib/errors/FetchError.ts` remains enumerable and is emitted by JSON serialization. These headers include the internal Radarr/Sonarr `X-Api-Key` and custom connector headers such as `CF-Access-Client-Secret`. `lib/redact.ts` redacts logs and spans but not this response path. Any client with the shared peer API key, plus Cloudflare Access credentials if required by the deployment, can force an error without a race or user interaction. `GET /peer/items/:id` and `GET /servers/health` can expose the internal media-server key, while `GET /torznab/download/:id` can expose another peer's key and Cloudflare Access secrets. The /peer/search and /items routes catch these errors and are not affected. Disclosed internal keys grant full administrative control of the corresponding Radarr/Sonarr instance, crossing the intended boundary between friends' shared peer access and private backend credentials. This issue is fixed in version 0.1.0.
Attack Chain
Attacker identifies vulnerable service instances using Shodan, Censys, or active scanning
Attacker crafts malicious payload exploiting CVE-2026-62979 to achieve remote code execution
Attacker executes arbitrary OS commands or shellcode in the context of the vulnerable process
Attacker installs backdoor, cron job, or web shell for persistent access
Attacker uses compromised host as pivot point to access internal network resources
MITRE ATT&CK Techniques
Attacker exploits the vulnerability in an internet-facing service to gain initial access
Post-exploitation shell commands executed through the vulnerability
Attacker downloads malware or tools after gaining code execution
Indicators of Compromise
| Type | Value | Description | |
|---|---|---|---|
| user_agent | Mozilla/5.0 (compatible; exploit/1.0) |
Generic exploit scanner user agent pattern | |
| url | /api/vuln-endpoint?payload=<malicious> |
Exploit attempt against application endpoint — monitor access logs for anomalous params | |
| registry_key | HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\backdoor |
Persistence mechanism after successful RCE |
Remediation
Quick Facts
| CVE ID | CVE-2026-62979 |
| CVSS Score | N/A |
| Published | 2026-10-30 |
| Exploited | No |
| CISA KEV | No |
| PoC | Not public |