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NVD / CVE Program· CNA Linux

CVE-2026-43350: smb: client: require a full NFS mode SID before reading mode bits

Noroxi assessment

Priority: Monitor (action score 30/100)

  • 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: 0.32% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 1592a6cd6f653f2d24572a6976c7a775b19f4940, 23b54d6cc3ef30a51d984dc74364f24039ae2ecb, 2757ad3e4b6f9e0fed4c7739594e702abc5cab21.

Low priority for now. Upgrade to Linux Linux 1592a6cd6f653f2d24572a6976c7a775b19f4940, 23b54d6cc3ef30a51d984dc74364f24039ae2ecb, 2757ad3e4b6f9e0fed4c7739594e702abc5cab21 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: smb: client: require a full NFS mode SID before reading mode bits parse_dacl() treats an ACE SID matching sid_unix_NFS_mode as an NFS mode SID and reads sid.sub_auth[2] to recover the mode bits. That assumes the ACE carries three subauthorities, but compare_sids() only compares min(a, b) subauthorities. A malicious server can return an ACE with num_subauth = 2 and sub_auth[] = {88, 3}, which still matches sid_unix_NFS_mode and then drives the sub_auth[2] read four bytes past the end of the ACE. Require num_subauth >= 3 before treating the ACE as an NFS mode SID. This keeps the fix local to the special-SID mode path without changing compare_sids() semantics for the rest of cifsacl.

HighCVSS 7.6 · v3.1—No exploit Fix available
Published
May 8, 2026
Updated
Oct 19, 2026
EPSS
0.3% · 25th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.6 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
7.6
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-2026-43350

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

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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.

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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.

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 kernel5.4 and later · before 6.6.136
  • linux linux kernel6.7 and later · before 6.12.84
  • linux linux kernel6.13 and later · before 6.18.25
  • linux linux kernel6.19 and later · before 7.0.2

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

    • 5.4affected
    • e2f8fbfb8d09c06decde162090fac3ee220aa280 and later · before 23b54d6cc3ef30a51d984dc74364f24039ae2ecbaffected · git
    • e2f8fbfb8d09c06decde162090fac3ee220aa280 and later · before 1592a6cd6f653f2d24572a6976c7a775b19f4940affected · git
    • e2f8fbfb8d09c06decde162090fac3ee220aa280 and later · before 8bd4cad3f458d11650d51c2d24b03fb1770ae6ccaffected · git
    • e2f8fbfb8d09c06decde162090fac3ee220aa280 and later · before b53b8e98c23310294fc45fc686db5ee860311896affected · git
    • e2f8fbfb8d09c06decde162090fac3ee220aa280 and later · before c8eef12af1cc73031639ea7cf16e0b10e2536b0baffected · git
    • e2f8fbfb8d09c06decde162090fac3ee220aa280 and later · before 38a69f08ee82c450d3e4168707fff2e317dc3ff7affected · git
    • e2f8fbfb8d09c06decde162090fac3ee220aa280 and later · before f8488c07bea2431ee12a6067d736578064fa46b4affected · git
    • e2f8fbfb8d09c06decde162090fac3ee220aa280 and later · before 2757ad3e4b6f9e0fed4c7739594e702abc5cab21affected · git
    • before 5.4not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.176-16.1.176-1
Debian:13linuxbefore 6.12.85-16.12.85-1
Debian:14linuxbefore 7.0.3-17.0.3-1

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-2026-43341May 8, 2026 · net/ipv6: ioam6: prevent schema length wraparound in trace fill
    39Monitor
  • ← EarlierCVE-2026-43346May 8, 2026 · ice: ptp: don't WARN when controlling PF is unavailable
    22Monitor
  • Later →CVE-2026-43352May 8, 2026 · i3c: mipi-i3c-hci: Correct RING_CTRL_ABORT handling in DMA dequeue
    31Monitor

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 Linux1592a6cd6f653f2d24572a6976c7a775b19f4940Vendor (CNA)
Linux Linux23b54d6cc3ef30a51d984dc74364f24039ae2ecbVendor (CNA)
Linux Linux2757ad3e4b6f9e0fed4c7739594e702abc5cab21Vendor (CNA)
Linux Linux38a69f08ee82c450d3e4168707fff2e317dc3ff7Vendor (CNA)
Linux Linux8bd4cad3f458d11650d51c2d24b03fb1770ae6ccVendor (CNA)
Linux Linuxb53b8e98c23310294fc45fc686db5ee860311896Vendor (CNA)
Linux Linuxc8eef12af1cc73031639ea7cf16e0b10e2536b0bVendor (CNA)
Linux Linuxf8488c07bea2431ee12a6067d736578064fa46b4Vendor (CNA)
debian:linux6.1.176-1 · 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.

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

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

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

Weakness class (CWE)

CWE-125 · Out-of-bounds Read

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/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.

ATT&CK techniques

—

Change log

  1. SSVC exploitation— → none
  2. Fix✗ → ✓

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

References

Show all references (8 more)

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

All records