{"cve":"CVE-2026-6386","nvd":{"published":"2026-04-22T03:16:01.313","modified":"2026-06-17T11:00:45.707","status":"Analyzed","description":"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.\n\nThe 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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","score":6.2},"cwes":["CWE-269","CWE-732"],"references":["https://security.freebsd.org/advisories/FreeBSD-SA-26:11.amd64.asc"],"products":["freebsd:freebsd"],"source":"nvd","synced_at":"2026-10-19T22:30:49.762551342+00:00"},"epss":{"cve":"CVE-2026-6386","score":0.00204,"percentile":0.10425,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}