CVE-2026-6386: In order to apply a particular protection key to an address range, the kernel must update the corresponding pa

Routine

MEDIUM 6.2MITIGATE

CVE-2026-6386 is a medium-severity flaw (CVSS 6.2) affecting freebsd. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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_

Why this priority

No elevated risk signals yet

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	6.2 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 90%)
CISA exploited list	No
Weakness	CWE-269, CWE-732
Published	2026-04-22
Last modified	2026-06-17

Publisher (CNA): FreeBSD · Vendor: freebsd

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-22 03:16 UTCPublished CVE record published
2026-06-17 11:00 UTCUpdated Record last modified

freebsd freebsd MITIGATE

Affected: 13.5 · 13.5 beta3 · 13.5 p1 · 13.5 p10 · 13.5 p11 · 13.5 p2 · 13.5 p3 · 13.5 p4

Fixed in: no fixed release known

Safe to downgrade to: a release before 13.5

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-6386?

freebsd: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-6386 being exploited?

CVE-2026-6386 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-6386 affect?

CVE-2026-6386 affects freebsd. Severity is medium (CVSS 6.2). 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 us

How urgent is CVE-2026-6386?

Priority 24/100. No elevated risk signals yet.

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References

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