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NVD / CVE Program· CNA Linux

CVE-2026-90155: ksmbd: detach blocked lock requests before freeing

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.21% (FIRST EPSS).
  • Fixed version: Linux Linux 215e8816b1ac25176d911abb8704390413ccee4b, 4e8b69c06bd6583ec11abef4fae50c2c8d5f3679, 514a0b2bc949963497e66cacd433f65dc768a71d.

Low priority for now. Upgrade to Linux Linux 215e8816b1ac25176d911abb8704390413ccee4b, 4e8b69c06bd6583ec11abef4fae50c2c8d5f3679, 514a0b2bc949963497e66cacd433f65dc768a71d or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: ksmbd: detach blocked lock requests before freeing A file_lock retained by ksmbd for byte-range lock bookkeeping can still be part of the VFS blocked-request graph. In particular, the VFS can chain a new waiter below an already blocked request through flc_blocked_requests. The ksmbd_file reference count does not cover that graph. Both __ksmbd_close_fd() and the cross-request unlock path free these retained file_lock objects directly. If a dependent waiter is still attached, locks_release_private() hits BUG_ON(!list_empty(&flc->flc_blocked_requests)). The same lifetime mismatch can leave a freed ksmbd_lock reachable through its request-local llist. Detach the file_lock from the blocked-request graph before freeing it in the close, cross-request unlock, and rollback paths. locks_delete_block() also wakes requests chained below the object. Remove llist when a completed lock is published so a globally visible ksmbd_lock no longer points into the submitting worker's stack.

—No exploit Fix available
Published
Sep 17, 2026
Updated
Oct 30, 2026
EPSS
0.2% · 11th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.15affected
    • d63528eb0d43c4796c42aad56889dec12cf4e122 and later · before 4e8b69c06bd6583ec11abef4fae50c2c8d5f3679affected · git
    • d63528eb0d43c4796c42aad56889dec12cf4e122 and later · before d20d3f6ad8b0b6f4e1bb32cdf7eca251962e8f04affected · git
    • d63528eb0d43c4796c42aad56889dec12cf4e122 and later · before d31db79cfaa9fce6649772ad279779473ba8aef9affected · git
    • d63528eb0d43c4796c42aad56889dec12cf4e122 and later · before f77d2accafca529e0ea3f979eb6e6cf1dac05c90affected · git
    • d63528eb0d43c4796c42aad56889dec12cf4e122 and later · before 514a0b2bc949963497e66cacd433f65dc768a71daffected · git
    • d63528eb0d43c4796c42aad56889dec12cf4e122 and later · before 215e8816b1ac25176d911abb8704390413ccee4baffected · git
    • before 5.15not affected · semver
    • 6.1.191 and later · up to and including 6.1.*not affected · semver
    • 6.6.160 and later · up to and including 6.6.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:14linuxbefore 7.2.6-17.2.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-90153Sep 17, 2026 · ksmbd: bound smb_check_perm_dacl() ACE walks by DACL size
    32Monitor
  • ← EarlierCVE-2026-90154Sep 17, 2026 · ksmbd: scope session state changes to bound connections
    0Monitor
  • Later →CVE-2026-90156Sep 17, 2026 · ksmbd: safely discard unregistered deferred locks
    0Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux215e8816b1ac25176d911abb8704390413ccee4bVendor (CNA)
Linux Linux4e8b69c06bd6583ec11abef4fae50c2c8d5f3679Vendor (CNA)
Linux Linux514a0b2bc949963497e66cacd433f65dc768a71dVendor (CNA)
Linux Linuxd20d3f6ad8b0b6f4e1bb32cdf7eca251962e8f04Vendor (CNA)
Linux Linuxd31db79cfaa9fce6649772ad279779473ba8aef9Vendor (CNA)
Linux Linuxf77d2accafca529e0ea3f979eb6e6cf1dac05c90Vendor (CNA)
debian:linux7.2.6-1 · Debian:14Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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References

Show all references (5 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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