Skip to content
Noroxi
NVD / CVE Program· CNA Linux

CVE-2026-31409: ksmbd: unset conn->binding on failed binding request

Noroxi assessment

Priority: Monitor (action score 35/100)

  • 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: 0.45% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 282343cf8a4a5a3603b1cb0e17a7083e4a593b03, 6260fc85ed1298a71d24a75d01f8b2e56d489a60, 6ebef4a220a1ebe345de899ebb9ae394206fe921.

Low priority for now. Upgrade to Linux Linux 282343cf8a4a5a3603b1cb0e17a7083e4a593b03, 6260fc85ed1298a71d24a75d01f8b2e56d489a60, 6ebef4a220a1ebe345de899ebb9ae394206fe921 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: unset conn->binding on failed binding request When a multichannel SMB2_SESSION_SETUP request with SMB2_SESSION_REQ_FLAG_BINDING fails ksmbd sets conn->binding = true but never clears it on the error path. This leaves the connection in a binding state where all subsequent ksmbd_session_lookup_all() calls fall back to the global sessions table. This fix it by clearing conn->binding = false in the error path.

HighCVSS 8.8 · v3.1—No exploit Fix available
Published
Apr 6, 2026
Updated
Aug 5, 2026
EPSS
0.4% · 39th percentile
CWE
—

Report tools

JSON

Action score

35

Monitor

Low priority for now.

CVSS
35 / 40 · 8.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CNA vs NVD score

NVD
—
CNA · Linux
8.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-31409

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits instantly.

Your free account also gets you

Running WordPress? Scan your site free with WP Lens

  • Stack alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every MondayDon't want an account? RSS feed for linux records

Running WordPress? Scan your site free with WP Lens

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

We use this product, ask for help

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.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel5.15 and later · before 6.1.167
  • linux linux kernel6.2 and later · before 6.6.130
  • linux linux kernel6.7 and later · before 6.12.78
  • linux linux kernel6.13 and later · before 6.18.20
  • linux linux kernel6.19 and later · before 6.19.10
  • linux linux kernel7.0

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
    • f5a544e3bab78142207e0242d22442db85ba1eff and later · before 7e8b270813079c785696bce8802a3f920665c88caffected · git
    • f5a544e3bab78142207e0242d22442db85ba1eff and later · before d073870dab8f6dadced81d13d273ff0b21cb7f4eaffected · git
    • f5a544e3bab78142207e0242d22442db85ba1eff and later · before 6ebef4a220a1ebe345de899ebb9ae394206fe921affected · git
    • f5a544e3bab78142207e0242d22442db85ba1eff and later · before 89afe5e2dbea6e9d8e5f11324149d06fa3a4efcaaffected · git
    • f5a544e3bab78142207e0242d22442db85ba1eff and later · before 9feb2d1bf86d9e5e66b8565f37f8d3a7d281a772affected · git
    • f5a544e3bab78142207e0242d22442db85ba1eff and later · before 6260fc85ed1298a71d24a75d01f8b2e56d489a60affected · git
    • f5a544e3bab78142207e0242d22442db85ba1eff and later · before 282343cf8a4a5a3603b1cb0e17a7083e4a593b03affected · git
    • before 5.15not affected · semver
    • 5.15.209 and later · up to and including 5.15.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.170-16.1.170-1
Debian:13linuxbefore 6.12.85-16.12.85-1
Debian:14linuxbefore 6.19.10-16.19.10-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-31405Apr 6, 2026 · media: dvb-net: fix OOB access in ULE extension header tables
    39Monitor
  • ← EarlierCVE-2026-31406Apr 6, 2026 · xfrm: Fix work re-schedule after cancel in xfrm_nat_keepalive_net_fini()
    31Monitor
  • Later →CVE-2026-31407Apr 6, 2026 · netfilter: conntrack: add missing netlink policy validations
    28Monitor

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 Linux282343cf8a4a5a3603b1cb0e17a7083e4a593b03Vendor (CNA)
Linux Linux6260fc85ed1298a71d24a75d01f8b2e56d489a60Vendor (CNA)
Linux Linux6ebef4a220a1ebe345de899ebb9ae394206fe921Vendor (CNA)
Linux Linux7e8b270813079c785696bce8802a3f920665c88cVendor (CNA)
Linux Linux89afe5e2dbea6e9d8e5f11324149d06fa3a4efcaVendor (CNA)
Linux Linux9feb2d1bf86d9e5e66b8565f37f8d3a7d281a772Vendor (CNA)
Linux Linuxd073870dab8f6dadced81d13d273ff0b21cb7f4eVendor (CNA)
debian:linux6.1.170-1 · Debian:12Package 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.

No history yet (it accumulates with the daily EPSS job).

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

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd-secondary

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✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (6 more)

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

All records