CVE-2026-64400: In the Linux kernel, the following vulnerability has been resolved: ksmbd: prevent path traversal bypass by r

Q: How do I fix CVE-2026-64400?

linux kernel: upgrade to 5.16, 6.2, 7.1.4. Exact commands for each OS are on this page.

Q: Is CVE-2026-64400 being exploited?

CVE-2026-64400 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-64400 affect?

CVE-2026-64400 affects linux kernel. Severity is high (CVSS 8.6). In the Linux kernel, the following vulnerability has been resolved: ksmbd: prevent path traversal bypass by restricting caseless retry ksmbd_vfs_path_lookup() enforces LOOKUP_BENEATH to restrict path resolution within the share root. When

Q: How urgent is CVE-2026-64400?

Priority 52/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

This month

HIGH 8.6REMOTEWATCHLISTUPGRADE

CVE-2026-64400 is a high-severity flaw (CVSS 8.6) affecting linux kernel. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In the Linux kernel, the following vulnerability has been resolved: ksmbd: prevent path traversal bypass by restricting caseless retry ksmbd_vfs_path_lookup() enforces LOOKUP_BENEATH to restrict path resolution within the share root. When a crafted path attempts to escape the share boundary using parent-directory components ('..'), vfs_path_parent_lookup() detects this and immediately fails, returning -EXDEV. However, a bug exists in __ksmbd_v

Why this priority

High severity
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	8.6 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 51%)
CISA exploited list	No
Published	2026-07-25
Last modified	2026-10-21

Publisher (CNA): kernel.org · Vendor: linux

Last updated 2026-10-21 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-25 10:17 UTCPublished CVE record published
2026-10-21 13:19 UTCUpdated Record last modified

linux linux kernel UPGRADE

Affected: >= 5.15.145 and < 5.16 · >= 6.1.71 and < 6.2 · >= 6.3.10 and < 7.1.4

Fixed in: 5.16, 6.2, 7.1.4

Safe to downgrade to: no unaffected older release

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-2026-64400?

linux kernel: upgrade to 5.16, 6.2, 7.1.4. Exact commands for each OS are on this page.

Is CVE-2026-64400 being exploited?

CVE-2026-64400 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-2026-64400 affect?

CVE-2026-64400 affects linux kernel. Severity is high (CVSS 8.6). In the Linux kernel, the following vulnerability has been resolved: ksmbd: prevent path traversal bypass by restricting caseless retry ksmbd_vfs_path_lookup() enforces LOOKUP_BENEATH to restrict path resolution within the share root. When

How urgent is CVE-2026-64400?

Priority 52/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Linux kernel vulnerabilities

Related CVEs

CVE-2026-63938 CRITICAL 9.3 UPGRADE In the Linux kernel, the following vulnerability has been resolved: KVM: SEV: Check PSC request indices again
CVE-2026-63937 HIGH 8.8 UPGRADE In the Linux kernel, the following vulnerability has been resolved: KVM: SEV: Use READ_ONCE() when reading en
CVE-2026-63927 HIGH 7.8 UPGRADE In the Linux kernel, the following vulnerability has been resolved: usb: dwc2: Fix use after free in debug co
CVE-2026-63925 HIGH 8.1 UPGRADE In the Linux kernel, the following vulnerability has been resolved: macsec: fix replay protection at XPN lowe
CVE-2026-63923 HIGH 8.8 UPGRADE In the Linux kernel, the following vulnerability has been resolved: octeontx2-af: validate body pcifunc in rv

References

← Back to latest CVEs