UgCS server HCI authentication bypass with empty credentials
- Exploited
- No known exploitation
- Fix
- Fixed in 6.2
- Who is exposed
- Default setups
Do first: Check every install: default setups are affected.
- Last modified
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 31/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Default setups
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
The UgCS server software, on installations that have only one user account, can be tricked into granting full access when a login request has empty credentials. A remote attacker who can reach the service on TCP port 3334 can do this without logging in, then issue privileged commands, including controlling connected drones and uploading flight routes.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
UgCS server before 6.2 contains an authentication bypass in the HCI protocol login handler (LoginHandler) exposed on TCP port 3334. When the user database contains exactly one user (the default single-operator installation), a LoginRequest with empty userLogin and userPassword fields is interpreted as \"use the only user\" rather than as invalid credentials, and the server returns a fully authenticated session. Because the service listens on all interfaces (0.0.0.0) without TLS by default, an unauthenticated remote attacker with network access to port 3334 can obtain an authenticated session without knowing any credential and then issue privileged commands, including commanding connected drones and uploading flight routes.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure22/25Default setups, reachable over the network without a login
- Reach?/20Unknown. No tracked technology or package matched
- Severity9.3/10CVSS 9.3
- No patch0/5No signal
What would change the score
- Would score about 71 if added to CISA KEV
- Would score about 66 if CISA's SSVC rates exploitation active
What to do
Check every install: default setups are affected.
Upgrade to a fixed version: 6.2.
Workaround: Bind the HCI listener to 127.0.0.1, restrict TCP port 3334 with host and network firewall rules, and place the service behind an authenticated TLS transport.
Timeline
- CVE published
- First seen by cve.now
- Posted on X by cve.now
Affected versions
- SPH Engineering UgCS
fixed in 6.2
Evidence 2
- Link
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-59104
Is CVE-2026-59104 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
When the UgCS server's user database holds exactly one account, a remote client can log in over the HCI interface with empty credentials and receive a fully authenticated session. From there it can issue privileged commands, including commanding connected drones and uploading flight routes.Source: offseq.com, cve.org
Which versions are affected by CVE-2026-59104?
UgCS: before 6.2.Source: cve.now feed data
Am I affected, and how do I check?
UgCS server versions before 6.2 on Windows, macOS and Linux are affected. The bug only applies when the user database contains exactly one account, and the HCI listener on TCP port 3334 binds to all interfaces without TLS, which is the default. To check, look at the installed UgCS server version and the number of accounts in its user database.Source: offseq.com, cve.org
How do I fix CVE-2026-59104?
Upgrade UgCS to version 6.2 or later, where empty credentials are no longer accepted as a valid login. Until the upgrade is done, the workaround listed for this issue applies.Source: offseq.com, cve.org