Raw vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/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:XSummary
CVE-2026-4391 is a medium-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Teamspeak Services (inferred from references). Its CVSS base score is 6.9 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 34th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SI-2 (Flaw Remediation) and RA-5 (Vulnerability Monitoring and Scanning) — see the control section below for these in your framework.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-32585
Vulnerability Data
A security vulnerability has been detected in TeamSpeak 3 Server up to 3.13.7. This vulnerability affects unknown code of the component ECC Key Parser. Such manipulation leads to heap-based buffer overflow. The attack may be launched remotely. Upgrading to version…
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3.13.8 is able to resolve this issue. It is suggested to upgrade the affected component.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Remote heap buffer overflow in public-facing TeamSpeak server component directly enables exploitation of a public-facing application (T1190).
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
Mitigating Controls (NIST 800-53 r5) AI
Directly requires timely application of the vendor patch that eliminates the heap buffer overflow in the ECC Key Parser.
Mandates vulnerability scanning that would identify the known ECC parser flaw in versions <= 3.13.7 before exploitation.
Enables continuous monitoring for anomalous network traffic or process behavior indicative of remote buffer-overflow attempts against the parser.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure-development practices directly require bounds checking and safe memory handling that prevent heap overflows.
Vulnerability scanning and code analysis directly surface buffer-boundary flaws.
Receiving and triaging vulnerability disclosures commonly includes buffer-related reports.
Developer training on secure coding reduces introduction of memory-buffer errors.
Patching replaces vulnerable code containing buffer-boundary defects.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development catches out-of-bounds accesses before release, covering most instances of the weakness.
Secure development lifecycle mandates memory-safety practices that directly prevent buffer-boundary violations.
Application security requirements can specify memory-safety rules, but do not prescribe implementation details.
Secure architecture and engineering principles include memory-safe design patterns that mitigate buffer overflows.
Secure coding standards explicitly forbid unsafe buffer operations, directly eliminating CWE-119.
Change management ensures controlled deployment of fixes for discovered heap-overflow vulnerabilities.