How severe is CVE-2026-3991?

CVE-2026-3991 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-3991 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (6th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-3991?

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.

Does CVE-2026-3991 have an EU (EUVD) identifier?

Yes. CVE-2026-3991 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-17164.

When was CVE-2026-3991 published?

CVE-2026-3991 was published on 2026-03-30 and last updated on 2026-06-17.

CVE-2026-3991

CVE-2026-3991 is a high-severity vulnerability with a CVSS 3.x base score of 7.8. 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-829.

Key facts

Severity: High (CVSS 3.x base score 7.8)
EPSS exploit prediction: 0% (6th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-17164
Weakness: CWE-829
Published: 2026-03-30
Last modified: 2026-06-17

Description

Symantec Data Loss Prevention Windows Endpoint, prior to 25.1 MP1, 16.1 MP2, 16.0 RU2 HF9, 16.0 RU1 MP1 HF12, and 16.0 MP2 HF15, may be susceptible to a Elevation of Privilege vulnerability, which is a type of issue whereby an attacker may attempt to compromise the software application to gain elevated access to resources that are normally protected from an application or user.

Frequently asked questions

What is CVE-2026-3991?: Symantec Data Loss Prevention Windows Endpoint, prior to 25.1 MP1, 16.1 MP2, 16.0 RU2 HF9, 16.0 RU1 MP1 HF12, and 16.0 MP2 HF15, may be susceptible to a Elevation of Privilege vulnerability, which is a type of issue whereby an attacker may attempt to compromise the software application to gain elevated access to resources that are normally protected from an application or user.
How severe is CVE-2026-3991?: CVE-2026-3991 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-3991 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (6th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-3991?: 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.
Does CVE-2026-3991 have an EU (EUVD) identifier?: Yes. CVE-2026-3991 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-17164.
When was CVE-2026-3991 published?: CVE-2026-3991 was published on 2026-03-30 and last updated on 2026-06-17.

References

https://support.broadcom.com/web/ecx/support-content-notification/-/external/content/SecurityAdvisories/0/37306

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