CVE-2026-6386 | FreeBSD Kernel pmap_pkru_update_range privileges management (EUVD-2026-24592)

VDB-358762 · CVE-2026-6386 · EUVD-2026-24592 FREEBSD KERNEL PMAP_PKRU_UPDATE_RANGE PRIVILEGES MANAGEMENT HISTORYDIFFRELATEJSONXMLCTI CVSS Meta Temp Score Current Exploit Price (≈) CTI Interest Score 7.6 $0-$5k 3.35+ Summaryinfo A vulnerability described as critical has been identified in FreeBSD. This affects the function pmap_pkru_update_range of the component Kernel. Executing a manipulation can lead to privileges management. This vulnerability is tracked as CVE-2026-6386. No exploit exists. A patch should be applied to remediate this issue. Detailsinfo A vulnerability has been found in FreeBSD (unknown version) and classified as critical. This vulnerability affects the function pmap_pkru_update_range of the component Kernel. The manipulation with an unknown input leads to a privileges management vulnerability. The CWE definition for the vulnerability is CWE-269. The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes: In order to apply a particular protection key to an address range, the kernel must update the corresponding page table entries. The subroutine which handled this failed to take into account the presence of 1GB largepage mappings created using the shm_create_largepage(3) interface. In particular, it would always treat a page directory page entry as pointing to another page table page. The bug can be abused by an unprivileged user to cause pmap_pkru_update_range() to treat userspace memory as a page table page, and thus overwrite memory to which the application would otherwise not have access. The weakness was disclosed by Nicholas Carlini. The advisory is available at security.freebsd.org. This vulnerability was named CVE-2026-6386 since 04/15/2026. The exploitation appears to be easy. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 04/22/2026). This vulnerability is assigned to T1068 by the MITRE ATT&CK project. Applying a patch is able to eliminate this problem. The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-24592). Productinfo Type Operating System Name FreeBSD License open-source Website Product: https://www.freebsd.org/ CPE 2.3info 🔒 CPE 2.2info 🔒 CVSSv4info VulDB Vector: 🔒 VulDB Reliability: 🔍 CVSSv3info VulDB Meta Base Score: 8.0 VulDB Meta Temp Score: 7.6 VulDB Base Score: 8.0 VulDB Temp Score: 7.6 VulDB Vector: 🔒 VulDB Reliability: 🔍 CVSSv2info Vector Complexity Authentication Confidentiality Integrity Availability Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock VulDB Base Score: 🔒 VulDB Temp Score: 🔒 VulDB Reliability: 🔍 Exploitinginfo Class: Privileges management CWE: CWE-269 / CWE-266 CAPEC: 🔒 ATT&CK: 🔒 Physical: No Local: No Remote: Partially Availability: 🔒 Status: Not defined Price Prediction: 🔍 Current Price Estimation: 🔒 0-Day Unlock Unlock Unlock Unlock Today Unlock Unlock Unlock Unlock Threat Intelligenceinfo Interest: 🔍 Active Actors: 🔍 Active APT Groups: 🔍 Countermeasuresinfo Recommended: Patch Status: 🔍 0-Day Time: 🔒 Timelineinfo 04/15/2026 CVE reserved 04/22/2026 +7 days Advisory disclosed 04/22/2026 +0 days VulDB entry created 04/22/2026 +0 days VulDB entry last update Sourcesinfo Product: freebsd.org Advisory: security.freebsd.org Researcher: Nicholas Carlini Status: Confirmed CVE: CVE-2026-6386 (🔒) GCVE (CVE): GCVE-0-2026-6386 GCVE (VulDB): GCVE-100-358762 EUVD: 🔒 Entryinfo Created: 04/22/2026 07:34 Updated: 04/22/2026 07:53 Changes: 04/22/2026 07:34 (55), 04/22/2026 07:53 (1) Complete: 🔍 Cache ID: 99:5F8:101 Discussion No comments yet. Languages: en. Please log in to comment. ◂ PreviousOverviewNext ▸