EUVD-2026-62588
GHSA-f8q9-f337-2p3r
Severity by source
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Network-reachable and unauthenticated (AV:N/PR:N) but the sandbox breakout requires a specific hard-to-meet condition (AC:H); escaping the isolated environment to the host is a scope change (S:C) with full C/I/A impact.
Primary rating from Vendor (kaspersky).
CVSS VectorVendor: kaspersky
Lifecycle Timeline
5DescriptionCVE.org
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 use a specially crafted script to break out of the isolated environment and execute arbitrary code on the host system.
Articles & Coverage 1
AnalysisAI
Remote code execution in TrueConf Server (versions 5.3.x through 5.3.9, 5.4.x through 5.4.9, 5.5.x through 5.5.5, and earlier) allows an unauthenticated network attacker reaching TCP port 4307 to submit a specially crafted script that escapes the product's isolated/sandboxed execution environment and runs arbitrary code on the underlying host. Reported by Kaspersky ICS-CERT and classified as CWE-94 code injection, the flaw carries a CVSS 4.0 base score of 9.5 driven by full confidentiality, integrity, and availability impact on both the vulnerable component and the host system it breaks out to. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | The concrete prerequisite is network reachability to TCP port 4307 on an affected TrueConf Server (5.3.x≤5.3.9, 5.4.x≤5.4.9, 5.5.x≤5.5.5, or earlier) plus the ability to submit a script to that port's interpreter feature; no authentication is required (PR:N) and no user interaction is needed (UI:N). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The signals are mixed but lean toward genuine priority: the impact ceiling is maximal (unauthenticated network-facing RCE with a scope change from a sandbox to the host, VC/VI/VA and SC/SI/SA all High), yet the vendor's own CVSS 4.0 vector tempers likelihood with AC:H (high attack complexity) and AT:P (a specific attack requirement / precondition must be met), indicating the breakout is not a trivial single-shot payload. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | No vendor-released patch version is identified in the available data; the affected ranges (up to 5.3.9, 5.4.9, and 5.5.5) imply a fixed build exists in a subsequent 5.5.x or later release, but the exact patched version is not confirmed here, so consult TrueConf's official release notes and the Kaspersky ICS-CERT advisory (https://ics-cert.kaspersky.com/advisories/2026/08/11/trueconf-server-breakout-from-isolated-environment/) to obtain and apply the corrected version. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours: Immediately restrict network access to TCP port 4307 to only trusted internal networks via firewall rules and document all systems running TrueConf Server versions 5.3.x through 5.5.5 in your asset inventory. …
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Same weakness CWE-94 – Code Injection
View allSame technique Code Injection
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External POC / Exploit Code
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