Command Injection in Ubiquiti UniFi OS package-update service
CVE-2026-34910 is an improper input validation vulnerability in Ubiquiti UniFi OS, specifically in the package-update service used by UniFi OS Server and referenced more broadly across UniFi OS devices. Available reporting indicates the vulnerable backend interpolated attacker-controlled package-name input into a shell command of the form sudo /usr/bin/uos runnable latest-versions %v and executed it via a sh -c wrapper without sufficient sanitization. This creates a command-injection condition that allows arbitrary shell metacharacters or crafted input to alter the intended command flow. Bishop Fox reporting further states the flaw was reachable in an unauthenticated exploit chain on UniFi OS Server 5.0.6 and earlier when combined with CVE-2026-34908 and CVE-2026-34909 to bypass authentication and reach the vulnerable package-update endpoint. The initial command execution occurs as the ucs-update service account rather than directly as root.
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Impact, mitigation & remediation
What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.
Impact
What an attacker gets, and what they’ve been doing with it.
ucs-update account. Reporting indicates that account has passwordless sudo access to several binaries, making escalation to root trivial on tested systems. Root compromise can expose highly sensitive material stored on the UniFi OS management plane, including JWT signing keys, TLS private keys, cloud-access tokens, PostgreSQL user data, RADIUS secrets, Wi-Fi credentials, VPN/WireGuard configurations, NFC card data, facial-recognition templates, and OS password hashes. A successful attacker may obtain persistent administrative control over the UniFi environment and potentially compromise managed network devices, surveillance systems, door-access systems, and associated identities.Mitigation
If you can’t patch tonight, do this now.
/api/auth/validate-sso/ combined with encoded traversal sequences and for access to ucs/update/latest_package, as well as suspicious child processes spawned by ucs-update and unexpected sudo activity. Use available safe detection tooling from Bishop Fox to identify vulnerable UniFi OS Server instances. If exploitation is suspected, perform incident response actions beyond patching, including credential and secret rotation, review for forged administrative sessions, and host-level forensic investigation.Remediation
Patch, then assume compromise.
ucs-update account. Where applicable, follow Ubiquiti’s product-specific fixed-version guidance for other affected UniFi OS devices. Because patching does not remediate prior compromise, organizations should also investigate for signs of exploitation, rotate exposed secrets, and invalidate trust material such as signing keys if compromise is suspected.Exploits
No valid public exploits. Mallory filtered out 1 candidate as fakes, detection scripts, or README-only repos.
All candidate exploits were filtered out by Mallory's validation.
Affected products & vendors
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
23 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A critical command injection vulnerability in UniFi OS Server.
A command injection vulnerability in Ubiquiti UniFi OS Server that, when chained with CVE-2026-34908 and CVE-2026-34909, enables unauthenticated remote code execution and trivial privilege escalation to root.
A command injection vulnerability in Ubiquiti UniFi OS Server that enables arbitrary command execution and, when chained with the other flaws, leads to unauthenticated root remote code execution.
An improper input validation command injection flaw in the UniFi OS package-update service that allows unauthenticated command execution when reached via the authentication bypass chain.
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Cross-references every affected SKU, including bundled OEM variants.
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