CVE-2026-3991
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-3991 is a high-severity Inclusion of Functionality from Untrusted Control Sphere (CWE-829) vulnerability in Broadcom (inferred from references). Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Supply Chain Compromise (T1195); ranked at the 9th 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 SR-4 (Provenance) and SR-11 (Component Authenticity) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
Symantec Data Loss Prevention Windows Endpoint versions prior to 25.1 MP1, 16.1 MP2, 16.0 RU2 HF9, 16.0 RU1 MP1 HF12, and 16.0 MP2 HF15 are affected by CVE-2026-3991, an Elevation of Privilege vulnerability (CWE-829). This flaw allows an attacker to compromise the software application and gain elevated access to resources that are normally protected from an application or user. The vulnerability has a CVSS v3.1 base score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H), indicating high impact on confidentiality, integrity, and availability with low attack complexity and prerequisites.
A local attacker with low privileges can exploit this vulnerability without user interaction. Successful exploitation enables the attacker to elevate their privileges, potentially compromising sensitive resources protected by the endpoint software and achieving high-impact effects across confidentiality, integrity, and availability.
The Broadcom security advisory at https://support.broadcom.com/web/ecx/support-content-notification/-/external/content/SecurityAdvisories/0/37306 details mitigation, recommending updates to Symantec Data Loss Prevention Windows Endpoint versions 25.1 MP1, 16.1 MP2, 16.0 RU2 HF9, 16.0 RU1 MP1 HF12, 16.0 MP2 HF15, or later to address the vulnerability.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-17164
Vulnerability Data
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…
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attacker may attempt to compromise the software application to gain elevated access to resources that are normally protected from an application or user.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 6 hardening rules · 6 OS baselines
V14.2.3V3.5.6V9.1.3V15.3.2
Mitigating Controls (NIST 800-53 r5) AI
Requires documented, valid provenance for components, preventing acceptance of code from outside the trusted sphere.
Implements detection and prevention of counterfeit or inauthentic components before they are integrated.
Establishes processes to identify and address supply-chain weaknesses that would allow untrusted functionality.
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.
Pre-acquisition integrity/authenticity checks directly prevent inclusion of untrusted code.
Supply-chain program directly governs inclusion of third-party executable code.
Contractual requirements can mandate trusted sources and integrity checks for included functionality.
Supplier risk assessment explicitly covers risks from their products and libraries.
Critical-supplier assessment reduces risk of importing executable functionality from untrusted parties.
Secure SDLC practices include dependency vetting and trusted-source policies.
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.
By requiring suppliers to propagate security requirements and to disclose component provenance, the control limits the inclusion of functionality obtained from untrusted third-party sources without oversight.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).
Oracle Linux 8 (1 rule)
- V-248635 Executable search paths within the initialization files of all local interactive OL 8 users must only contain paths that resolve to the system default or the user's home directory. prevents CWE-829
Oracle Linux 9 (1 rule)
- V-271847 OL 9 must be configured so that executable search paths within the initialization files of all local interactive users must only contain paths that resolve to the system default or the users home directory. prevents CWE-829
RHEL 7 (1 rule)
- V-204477 The Red Hat Enterprise Linux operating system must be configured so that all local interactive user initialization files executable search paths contain only paths that resolve to the users home directory. prevents CWE-829
RHEL 8 (1 rule)
- V-230317 Executable search paths within the initialization files of all local interactive RHEL 8 users must only contain paths that resolve to the system default or the users home directory. prevents CWE-829
RHEL 9 (1 rule)
- V-258050 Executable search paths within the initialization files of all local interactive RHEL 9 users must only contain paths that resolve to the system default or the users home directory. prevents CWE-829
Windows 10 (1 rule)
- V-220737 Administrative accounts must not be used with applications that access the Internet, such as web browsers, or with potential Internet sources, such as email. prevents CWE-829