How severe is CVE-2020-10656?

CVE-2020-10656 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-10656 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (83rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-10656?

CVE-2020-10656 affects Proofpoint Insider Threat Management Server. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-10656?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2020-10656 published?

CVE-2020-10656 was published on 2021-01-06 and last updated on 2026-06-17.

CVE-2020-10656

CVE-2020-10656 is a critical-severity vulnerability in Proofpoint Insider Threat Management Server with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-502.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 3% (83rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-502
Affected product: Proofpoint Insider Threat Management Server
Published: 2021-01-06
Last modified: 2026-06-17

Description

The Proofpoint Insider Threat Management Server (formerly ObserveIT Server) before 7.9.1 contains a vulnerability in the ITM application server's WriteWindowMouseWithChunksV2 API. The vulnerability allows an anonymous remote attacker to execute arbitrary code with local administrator privileges. The vulnerability is caused by improper deserialization.

Frequently asked questions

What is CVE-2020-10656?: The Proofpoint Insider Threat Management Server (formerly ObserveIT Server) before 7.9.1 contains a vulnerability in the ITM application server's WriteWindowMouseWithChunksV2 API. The vulnerability allows an anonymous remote attacker to execute arbitrary code with local administrator privileges. The vulnerability is caused by improper deserialization.
How severe is CVE-2020-10656?: CVE-2020-10656 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-10656 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (83rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-10656?: CVE-2020-10656 affects Proofpoint Insider Threat Management Server. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-10656?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2020-10656 published?: CVE-2020-10656 was published on 2021-01-06 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:proofpoint:insider_threat_management_server:*:*:*:*:*:*:*:*

More vulnerabilities in Proofpoint Insider Threat Management Server

CVE-2021-40842 — Critical (CVSS 9.8): Proofpoint Insider Threat Management Server contains a SQL injection vulnerability in the Web Console. The…
CVE-2020-10658 — Critical (CVSS 9.8): The Proofpoint Insider Threat Management Server (formerly ObserveIT Server) before 7.9.1 contains a vulnerability in…
CVE-2020-10655 — Critical (CVSS 9.8): The Proofpoint Insider Threat Management Server (formerly ObserveIT Server) before 7.9.1 contains a vulnerability in…
CVE-2021-40843 — High (CVSS 7.3): Proofpoint Insider Threat Management Server contains an unsafe deserialization vulnerability in the Web Console. An…
CVE-2020-10657 — High (CVSS 7.2): The Proofpoint Insider Threat Management Server (formerly ObserveIT Server) before 7.9.1 contains a vulnerability in…
CVE-2023-36000 — Medium (CVSS 6.5): A missing authorization check in the MacOS agent configuration endpoint of the Insider Threat Management Server enables…

All CVEs affecting Proofpoint Insider Threat Management Server →

Other CWE-502 (Deserialization of Untrusted Data) vulnerabilities

CVE-2026-41104 — Critical (CVSS 10.0): Deserialization of untrusted data in Microsoft Planetary Computer Pro allows an unauthorized attacker to disclose…
CVE-2026-43633 — Critical (CVSS 10.0): HestiaCP versions 1.9.0 through 1.9.4 contain a deserialization vulnerability in the web terminal component caused by a…
CVE-2026-33819 — Critical (CVSS 10.0): Deserialization of untrusted data in Microsoft Bing allows an unauthorized attacker to execute code over a network.
CVE-2026-20131 — Critical (CVSS 10.0): A vulnerability in the web-based management interface of Cisco Secure Firewall Management Center (FMC) Software could…
CVE-2026-25632 — Critical (CVSS 10.0): EPyT-Flow is a Python package designed for the easy generation of hydraulic and water quality scenario data of water…
CVE-2025-14931 — Critical (CVSS 10.0): Hugging Face smolagents Remote Python Executor Deserialization of Untrusted Data Remote Code Execution Vulnerability.…

Browse all CWE-502 (Deserialization of Untrusted Data) vulnerabilities →