What happened
CVE-2026-48558 (CVSS 10, CWE-347) is a critical authentication bypass in SimpleHelp's OIDC flow: identity tokens submitted during login are accepted without verifying their cryptographic signature, allowing an unauthenticated attacker to forge a token and obtain a fully authenticated technician session. Added to CISA KEV on 2026-06-29 with a federal due date of 2026-07-02. Blackpoint's Adversary Pursuit Group confirmed active exploitation deploying two malware families: TaskWeaver (a Node.js obfuscated loader disguised as jquery.js) and Djinn Stealer, a cross-platform infostealer targeting cloud credentials, SSH keys, CI/CD tokens, cryptocurrency wallets, and — critically — AI development tool credentials and MCP server configuration tokens.
Why it matters
Djinn Stealer explicitly harvests authentication data for AI development tools and MCP configurations. Stolen MCP tokens can grant attackers access to every repository, database, and cloud service connected to an AI assistant. SimpleHelp is used by 6,000+ organisations managing millions of endpoints. Compromise of a single SimpleHelp instance gives attacker full RMM-level access to all managed systems, making the AI credential theft a force-multiplier for broader supply-chain compromise.
Attack vector
Unauthenticated attacker sends a forged OIDC identity token to an internet-facing SimpleHelp server, obtains a privileged technician session, then uses that session to deploy TaskWeaver and Djinn Stealer to all managed endpoints via RMM file transfer and command execution.
Affected systems
SimpleHelp (all versions with OIDC authentication enabled, prior to the 2026-05 security update)
Mitigation
Apply SimpleHelp security update from https://simple-help.com/security/simplehelp-security-update-2026-05 immediately. Federal agencies must patch by 2026-07-02 per CISA BOD 26-04.