How severe is CVE-2018-8311?

CVE-2018-8311 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2018-8311 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 17% (97th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-8311?

CVE-2018-8311 primarily affects Microsoft Lync. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-8311?

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

When was CVE-2018-8311 published?

CVE-2018-8311 was published on 2018-07-11 and last updated on 2026-06-17.

CVE-2018-8311

CVE-2018-8311 is a high-severity vulnerability in Microsoft Lync with a CVSS 3.x base score of 8.8. Its EPSS exploit-prediction score of 17% places it in the 97th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-20.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 6.8
EPSS exploit prediction: 17% (97th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Microsoft Lync
Published: 2018-07-11
Last modified: 2026-06-17

Description

A remote code execution vulnerability exists when Skype for Business and Microsoft Lync clients fail to properly sanitize specially crafted content, aka "Remote Code Execution Vulnerability in Skype For Business and Lync." This affects Skype, Microsoft Lync.

Frequently asked questions

What is CVE-2018-8311?: A remote code execution vulnerability exists when Skype for Business and Microsoft Lync clients fail to properly sanitize specially crafted content, aka "Remote Code Execution Vulnerability in Skype For Business and Lync." This affects Skype, Microsoft Lync.
How severe is CVE-2018-8311?: CVE-2018-8311 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2018-8311 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 17% (97th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-8311?: CVE-2018-8311 primarily affects Microsoft Lync. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-8311?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2018-8311 published?: CVE-2018-8311 was published on 2018-07-11 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:microsoft:lync:-:sp1:*:*:*:*:*:*
cpe:2.3:a:microsoft:skype_for_business:-:*:*:*:*:*:*:*

More vulnerabilities in Microsoft Lync

CVE-2020-1025 — Critical (CVSS 9.8): An elevation of privilege vulnerability exists when Microsoft SharePoint Server and Skype for Business Server…
CVE-2016-7182 — Critical (CVSS 9.8): The Graphics component in Microsoft Windows Vista SP2; Windows Server 2008 SP2 and R2 SP1; Windows 7 SP1; Windows 8.1;…
CVE-2015-6108 — Critical (CVSS 9.3): The Windows font library in Microsoft Windows Vista SP2; Windows Server 2008 SP2 and R2 SP1; Windows 7 SP1; Windows 8;…
CVE-2015-6107 — Critical (CVSS 9.3): The Windows font library in Microsoft Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8,…
CVE-2015-6106 — Critical (CVSS 9.3): The Windows font library in Microsoft Windows Vista SP2, Windows Server 2008 SP2, Office 2007 SP3, Office 2010 SP2,…
CVE-2015-2503 — Critical (CVSS 9.3): Microsoft Access 2007 SP3, Excel 2007 SP3, InfoPath 2007 SP3, OneNote 2007 SP3, PowerPoint 2007 SP3, Project 2007 SP3,…

All CVEs affecting Microsoft Lync →

Other CWE-20 (Improper Input Validation) vulnerabilities

CVE-2026-48316 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48281 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48277 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48055 — Critical (CVSS 10.0): Streambert is a cross-platform Electron Desktop App to stream and download any video media. In versions 2.4.0 and…
CVE-2026-34910 — Critical (CVSS 10.0): A malicious actor with access to the network could exploit an Improper Input Validation vulnerability found in UniFi OS…
CVE-2026-33587 — Critical (CVSS 10.0): Lack of user input sanitisation in Open Notebook v1.8.3 allows the application user to execute Python code (and…

Browse all CWE-20 (Improper Input Validation) vulnerabilities →