CVE-2026-72529
CVE-2026-72529 — TrueConf Server Missing Authentication for Critical Function Vulnerability
A remote unauthorized attacker with network access via port 4307/TCP to the TrueConf server versions 5.3.X to 5.3.9, 5.4.X to 5.4.9, 5.5.X to 5.5.5, and earlier could execute an arbitrary script by calling an undocumented function.
Published Updated Sources: NVD, TrueConf (CNA), CISA, FIRST EPSS, GitHub, SOCRadar CTI
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.
Exploitation
Confirmed
CISA KEV, listed Aug 20, 2026
EPSS
2%
ahead of 73% of scored CVEs
CVSS base
9.8
critical · 2 sources
CISA SSVC assessment
Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.
Exploitation
Active
none · proof-of-concept · active
Automatable
Yes
can an attacker script all four kill-chain steps
Technical impact
Total
partial · total control of the vulnerable component
Remediation
The vendor's own words where we have them.
Update TrueConf server to versions 5.3.9, 5.4.9 or 5.5.5.
CISA required action
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Federal deadline Aug 23, 2026 — passed 7 days ago
First 24 hours
Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.
- Identify exposed assets running affected vendor/product/version combinations.
- Treat as emergency remediation because CISA KEV status is present.
- Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.
Affected scope
Vendor, product and version as the advisories word them.
| Vendor | Product | Versions | Status |
|---|---|---|---|
| TrueConf | TrueConf Server | * to < 5.3 | Vulnerable |
| TrueConf | TrueConf Server | 5.3 to < 5.3.9 | Vulnerable |
| TrueConf | TrueConf Server | 5.4 to < 5.4.9 | Vulnerable |
| TrueConf | TrueConf Server | 5.5 to < 5.5.5 | Vulnerable |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Availability
High
Confidentiality
High
Integrity
High
Scope
Unchanged
Attack Complexity
Low
Attack Vector
Network
Privileges Req
None
User Interaction
None
Every base score collected
Sources score independently and disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Source |
|---|---|---|---|---|---|
| 9.8 | CVSS 3.1 | critical | 3.9 | 5.9 | kaspersky.com (CNA), TrueConf (CNA) |
| 9.3 | CVSS 4.0 | critical | — | — | TrueConf (CNA) |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
What this weakness leads to
MITRE's own consequences and mitigations for the weakness class — the authority's wording, not guidance derived from the CVSS vector.
CWE-306 · Missing Authentication for Critical Function
- Gain Privileges or Assume Identity
- Other
Mitigation: Divide the software into anonymous, normal, privileged, and administrative areas. Identify which of these areas require a proven user identity, and use a centralized authentication capability. Identify all potential communication channels, or other means of interaction with the software, to ensure that all channels are appropriately protected. Developers sometimes perform authentication at the primary channel, but open up a secondary channel that is assumed to be private. For example, a login mechanism may be listening on one network port, but after successful authentication, it may open up a second port where it waits for the connection, but avoids authentication because it assumes that only the authenticated party will connect to the port. In general, if the software or protocol allows a single session or user state to persist across multiple connections or channels, authentication and appropriate credential management need to be used throughout.
Weakness & attack patterns
- CWE-306Missing Authentication for Critical Function
Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.
CISA KEV details
CISA lists a CVE here once it has evidence of exploitation against real targets.
Listed
Aug 20, 2026
Federal deadline
Aug 23, 2026
passed 7 days ago
Ransomware use
Unknown
CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a date to argue against.
Public exploit
Capability, not use: code existing is a different claim from anyone running it.
Repositories
1
Detection
Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.
- Search application, proxy, and WAF logs for requests touching /TCP.
- Prioritize edge telemetry for network-reachable TrueConf Server.
- Monitor for scanner or exploit-pattern traffic after 1 public PoC repositories were reported.
Timeline
What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.
- 2026
Added to CISA KEV catalog
Aug 20, 2026 · CISA
Added · CVSS 3.1 9.8 (AV:N)
Aug 19, 2026 · NVD
Initial · CVE published
Aug 19, 2026 · NVD
Reported · Advisory published by Kaspersky ICS CERT
Aug 7, 2026 · TrueConf
Reported · Issue confirmed by TrueConf
Aug 4, 2026 · TrueConf
Issue discovered by Kaspersky ICS CERT and reported to TrueConf
Aug 3, 2026 · TrueConf
References
7 on the record
- ics-cert.kaspersky.com/advisories/2026/08/11/trueconf-server-missing-authentication-for-critical-function/
Vendor Advisory
- securelist.com/tr/head-mare-targets-trueconf-server-with-phantomcore/120988/
Vendor Advisory
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-72529
US Government Resource
- trueconf.com/blog/news/security-fixes-updates-and-advisories
Vendor Advisory
- www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
US Government Resource
- www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
US Government Resource
- nvd.nist.gov/vuln/detail/CVE-2026-72529
Vendor Advisory
Elsewhere on this site
- TrueConfevery CVE for this vendor
- August 2026what else CISA listed
- Auth Bypasssame class
- CWE-306other pages naming this weakness
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record1
What should defenders know first?
CVE-2026-72529 is TrueConf Server Missing Authentication for Critical Function Vulnerability, a critical vulnerability affecting TrueConf Server from TrueConf. The current evidence lists it in CISA KEV, and the exploit status is: Yes: CISA KEV signal present. Public exploit evidence is: 1 public PoC repositories reported; 0 marked weaponized in current dataset. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 9.8 describes technical severity, while EPSS 2% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.