Read the docs
TI-2026-45964 Aliases CVE-2026-64400GHSA-cg5c-7728-29v7

ksmbd: prevent path traversal bypass by restricting caseless retry

Priority LOW 38Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
Low · Low · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA.

Summary

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_vfs_kern_path() under caseless mode. The function fails to intercept the -EXDEV error and erroneously falls through to the caseless retry logic, which is intended only for genuinely missing files. During this retry process, the path is reconstructed, leading to an unintended LOOKUP_BENEATH bypass that allows write-capable users to create zero-length files or directories outside the exported share. Fix this by ensuring that the execution only proceeds to the caseless lookup retry when the error is specifically -ENOENT. Any other errors, such as -EXDEV from a path traversal attempt, must be returned immediately.

Why it matters now

EPSS 0.00447 39th percentileScored 2026-11-07
Fix Fixed Linux (Linux): 6.1.191, 5.16, 6.4 +5

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux6.1.71 to before 6.1.191; 5.15.145 to before 5.16; 6.3.10 to before 6.46.1.191, 5.16, 6.4Patch availableCNA
LinuxLinux6.4 and later6.1.191, 6.6.160, 6.12.114, 6.18.57, 7.1.4, 7.2Patch availableCNA
  • Linux VendorLinux Affected 6.1.71 to before 6.1.191; 5.15.145 to before 5.16; 6.3.10 to before 6.4 Fixed in 6.1.191, 5.16, 6.4 Patch available CNA
  • Linux VendorLinux Affected 6.4 and later Fixed in 6.1.191, 6.6.160, 6.12.114, 6.18.57, 7.1.4, 7.2 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*5.15.145 to before 5.16; 6.1.71 to before 6.2; 6.3.10 to before 7.1.4VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 5.15.145 to before 5.16; 6.1.71 to before 6.2; 6.3.10 to before 7.1.4 Vulnerable ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 6.1.191, 5.16, 6.4
  • Fix · CNA Linux (Linux) Fixed in 6.1.191, 6.6.160, 6.12.114, 6.18.57, 7.1.4, 7.2

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

Not affected: 5 products
  • Red Hat Enterprise Linux 10
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-64400
  2. 2026-10-03 Alias added: GHSA-cg5c-7728-29v7
  3. 2026-10-16 Fix available: Linux/[email protected], Linux/Linux@cfb5a56c218888f9d74165dff0c282cd0be97983 · CNA
  4. 2026-10-16 1 new reference · CNA
  5. 2026-10-20 Affected versions changed · Red Hat
  6. 2026-10-21 Fix available: Linux/[email protected], Linux/[email protected], Linux/Linux@a1c331d98313380c38f616c8b28b890ec8ef9c28 +1 · CNA
  7. 2026-10-21 2 new references · CNA
  8. 2026-10-30 Fix available: Linux/Linux@21f050439db157f2afcc19885dec14549ca6ffc0, Linux/[email protected] · CNA
  9. 2026-10-30 1 new reference · CNA
  10. 2026-10-31 EPSS moved to the 50th–90th percentile
  11. 2026-11-04 EPSS moved to the below the 50th percentile

References

Patch 2

Other 4

  • TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
  • TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
  • TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
  • TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
  • TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
See all 15278 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences