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NVD / CVE Program· CNA Linux

CVE-2026-99276: ksmbd: defer connection scavenging while session locks are busy

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: 0.14% (FIRST EPSS).
  • Fixed version: Linux Linux 4e4e8b38994a0b0fc23f00ca6698b469a41abe70, 7.3, b4bae7af1154089be87c7475218264fcbfd16d10.

Low priority for now. Upgrade to Linux Linux 4e4e8b38994a0b0fc23f00ca6698b469a41abe70, 7.3, b4bae7af1154089be87c7475218264fcbfd16d10 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: defer connection scavenging while session locks are busy The expiration worker holds conn_list_lock for reading while checking for authenticated sessions. Without this change, the check can wait for conn->session_lock or sessions_table_lock. In destroy_previous_session(), the status updates after ksmbd_conn_wait_idle_sess() run with both session locks held for writing. Both the KSMBD_SESS_GOOD error path and the KSMBD_SESS_NEED_SETUP success path call ksmbd_all_conn_set_status(), which takes conn_list_lock for reading. A writer queued on conn_list_lock can block these new read acquisitions. The worker then waits for a session lock held by destroy_previous_session(), which waits behind the writer. The writer cannot proceed until the worker releases conn_list_lock. Try both session locks instead of waiting in the scavenging check. Keep the connection when either lock is busy and let the periodic worker retry later.

—No exploit Fix available
Published
Nov 7, 2026
Updated
Nov 7, 2026
EPSS
0.1% · 3th 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 · 0.1%

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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

    • c99ea7855124ca1428a1e59c2b4590aaef34eacf, 7.3affected
    • d7fd1f98607f2cd358e583f9548bdf0173090a86 and later · before 4e4e8b38994a0b0fc23f00ca6698b469a41abe70affected · git
    • d7fd1f98607f2cd358e583f9548bdf0173090a86 and later · before b4bae7af1154089be87c7475218264fcbfd16d10affected · git
    • 7.2.8 and later · before 7.3affected · semver
    • before 7.3not affected · semver
    • 7.3.2 and later · up to and including 7.3.*not affected · semver
    • 7.4-rc1 and laternot affected · original_commit_for_fix

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:14linuxfrom 0—

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-2026-99274Nov 7, 2026 · smb: client: fix fiemap wild read on empty truncated response
    0Monitor
  • ← EarlierCVE-2026-99275Nov 7, 2026 · smb: client: reject short SESSION_SETUP responses
    0Monitor
  • Later →CVE-2026-99277Nov 7, 2026 · ksmbd: hold a connection reference for each session channel
    30Monitor

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 Linux4e4e8b38994a0b0fc23f00ca6698b469a41abe70Vendor (CNA)
Linux Linux7.3Vendor (CNA)
Linux Linuxb4bae7af1154089be87c7475218264fcbfd16d10Vendor (CNA)

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.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 11, 2026+4 d
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

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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✗ → ✓
  2. Exploit maturity— → none

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References

Show all references (1 more)

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

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