Cyber Resilience

CVE-2018-15381

RCE in Cisco Unity Express ≤ 9.0.6

Published
08 November 2018
Modified
21 November 2024
Patch / advisory
CVSS Score v3 9.8
Click a component to see what it means
Raw vectorCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.87 99.7th percentile
Risk Priority 97 floored blend · peak EPSS

Summary

CVE-2018-15381 is a critical-severity Deserialization of Untrusted Data (CWE-502) vulnerability in Cisco Unity Express. Its CVSS base score is 9.8 (Critical).

Operationally, ranked in the top 0.3% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

A Java deserialization vulnerability in Cisco Unity Express (CUE) could allow an unauthenticated, remote attacker to execute arbitrary shell commands with the privileges of the root user. The vulnerability is due to insecure deserialization of user-supplied content by the affected…

more

software. An attacker could exploit this vulnerability by sending a malicious serialized Java object to the listening Java Remote Method Invocation (RMI) service. A successful exploit could allow the attacker to execute arbitrary commands on the device with root privileges.

CWE(s)

Related Threats

Likely ATT&CK TechniquesAI

Techniques this vulnerability likely enables, inferred from its description, weakness type, and attributed-actor tradecraft. Confidence is per-technique.

T1190 Exploit Public-Facing Application Initial Accessconfidence: HIGH
Unauthenticated remote exploitation of a public-facing Java RMI service via malicious serialized objects.
T1059.004 Unix Shell Executionconfidence: HIGH
Successful exploitation results in arbitrary shell command execution with root privileges.
T1068 Exploitation for Privilege Escalation Privilege Escalationconfidence: HIGH
Remote code execution directly grants root-level privileges on the target system.
inferred from description + CWE · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2024-20253Same vendor: Cisco
CVE-2025-20276Same vendor: Cisco
CVE-2025-20124Same vendor: Cisco
CVE-2023-20102Same vendor: Cisco
CVE-2026-20131Same vendor: Cisco
CVE-2025-20275Same vendor: Cisco
CVE-2019-15271Same vendor: Cisco
CVE-2018-0147Same vendor: Cisco
CVE-2019-12630Same vendor: Cisco
CVE-2020-27131Same vendor: Cisco

Affected Assets

cisco
unity express
≤ 9.0.6

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-502

Penetration testing supplies malicious serialized objects, detecting unsafe deserialization and supporting corrective actions.

addresses: CWE-502

Evaluation of untrusted data handling (deserialization testing) reveals unsafe processing, which the required remediation process addresses.

addresses: CWE-502

Untrusted serialized data can be deserialized and observed inside the chamber, blocking gadget-chain exploitation outside the sandbox.

addresses: CWE-502

Validates or rejects untrusted serialized data before deserialization occurs.

addresses: CWE-502

Identifies and blocks malicious code introduced through deserialization of untrusted data at system boundaries.

addresses: CWE-502

Integrity verification of serialized information can detect tampering before deserialization occurs.

addresses: CWE-502

Provenance of associated data allows detection of untrusted sources before deserialization or processing occurs.

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.

PR.PS-02 none match
prevents

PR.PS-02 addresses only post-deployment updates/patching and cannot prevent introduction of unsafe deserialization code, yet it can remediate some instances when the flaw exists in outdated libraries or components.

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.

detects

Security testing includes validation of deserialization routines and the use of untrusted data, reducing the likelihood that unsafe object reconstruction will be deployed.

prevents

Requiring vetted libraries, regular updates and SAST before release reduces the likelihood that deserialization logic will accept and act on attacker-controlled serialized objects.

detects

Regular scanning of third-party libraries and timely patching reduce the likelihood that unsafe deserialization vulnerabilities remain active.

none

Mandatory malware scanning of data received over networks or storage media intercepts malicious serialized payloads before they are deserialized by the target application.

References