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NVD / CVE Program· CNA Linux

CVE-2026-43040: net: ipv6: ndisc: fix ndisc_ra_useropt to initialize nduseropt_padX fields to zero to prevent an info-leak

Noroxi assessment

Priority: Monitor (action score 28/100)

  • 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: 0.12% (FIRST EPSS).
  • Someone with local access to the system 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 11d7fe97421cfc81549940c20ed5ac9472d6db05, 1da9023f6b071a38e5430ffbce4b70b2b1ac4f9c, 2fe4d0ba690a69ad6ae9f7ab9bdc96e02610b648.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 11d7fe97421cfc81549940c20ed5ac9472d6db05, 1da9023f6b071a38e5430ffbce4b70b2b1ac4f9c, 2fe4d0ba690a69ad6ae9f7ab9bdc96e02610b648 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: net: ipv6: ndisc: fix ndisc_ra_useropt to initialize nduseropt_padX fields to zero to prevent an info-leak When processing Router Advertisements with user options the kernel builds an RTM_NEWNDUSEROPT netlink message. The nduseroptmsg struct has three padding fields that are never zeroed and can leak kernel data The fix is simple, just zeroes the padding fields.

HighCVSS 7.1 · v3.1—No exploit Fix available
Published
May 1, 2026
Updated
Oct 15, 2026
EPSS
0.1% · 2th percentile

Report tools

JSON

Action score

28

Monitor

Low priority for now.

CVSS
28 / 40 · 7.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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-2026-43040

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 kernel2.6.24 and later · before 5.10.253
  • linux linux kernel5.11 and later · before 5.15.203
  • linux linux kernel5.16 and later · before 6.1.168
  • linux linux kernel6.2 and later · before 6.6.134
  • linux linux kernel6.7 and later · before 6.12.81
  • linux linux kernel6.13 and later · before 6.18.22
  • linux linux kernel6.19 and later · before 6.19.12
  • 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

    • 2.6.24affected
    • 31910575a9de61e78065e93846e8e7a4894a18bf and later · before 1da9023f6b071a38e5430ffbce4b70b2b1ac4f9caffected · git
    • 31910575a9de61e78065e93846e8e7a4894a18bf and later · before 2fe4d0ba690a69ad6ae9f7ab9bdc96e02610b648affected · git
    • 31910575a9de61e78065e93846e8e7a4894a18bf and later · before 11d7fe97421cfc81549940c20ed5ac9472d6db05affected · git
    • 31910575a9de61e78065e93846e8e7a4894a18bf and later · before 7f56d87e527bb5a13c3e8b0d5840cb6332822f6daffected · git
    • 31910575a9de61e78065e93846e8e7a4894a18bf and later · before 4f810c686fde509d1cdaa706322d9d2531f8f1a4affected · git
    • 31910575a9de61e78065e93846e8e7a4894a18bf and later · before b485eef3d97b7aae55ce669b6de555ec81f3d21caffected · git
    • 31910575a9de61e78065e93846e8e7a4894a18bf and later · before ef3645606e4a635d5062a492f22b7f490852ee67affected · git
    • 31910575a9de61e78065e93846e8e7a4894a18bf and later · before ae05340ccaa9d347fe85415609e075545bec589faffected · git
    • before 2.6.24not 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 6.19.12-16.19.12-1

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-2026-43037May 1, 2026 · ip6_tunnel: clear skb2->cb[] in ip4ip6_err()
    39Monitor
  • ← EarlierCVE-2026-43038May 1, 2026 · ipv6: icmp: clear skb2->cb[] in ip6_err_gen_icmpv6_unreach()
    39Monitor
  • Later →CVE-2026-43042May 1, 2026 · mpls: add seqcount to protect the platform_label{,s} pair
    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 Linux11d7fe97421cfc81549940c20ed5ac9472d6db05Vendor (CNA)
Linux Linux1da9023f6b071a38e5430ffbce4b70b2b1ac4f9cVendor (CNA)
Linux Linux2fe4d0ba690a69ad6ae9f7ab9bdc96e02610b648Vendor (CNA)
Linux Linux4f810c686fde509d1cdaa706322d9d2531f8f1a4Vendor (CNA)
Linux Linux7f56d87e527bb5a13c3e8b0d5840cb6332822f6dVendor (CNA)
Linux Linuxae05340ccaa9d347fe85415609e075545bec589fVendor (CNA)
Linux Linuxb485eef3d97b7aae55ce669b6de555ec81f3d21cVendor (CNA)
Linux Linuxef3645606e4a635d5062a492f22b7f490852ee67Vendor (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.

  • CVE-2026-6403579 days apartigc: set tx buffer type for SMD frames
    39Monitor
  • CVE-2022-50169317 days apartwifi: wil6210: debugfs: fix info leak in wil_write_file_wmi()
    28Monitor
  • CVE-2022-49865365 days apartipv6: addrlabel: fix infoleak when sending struct ifaddrlblmsg to network
    28Monitor
  • CVE-2025-38601255 days apartwifi: ath11k: clear initialized flag for deinit-ed srng lists
    22Monitor
  • CVE-2025-38532258 days apartnet: libwx: properly reset Rx ring descriptor
    22Monitor
  • CVE-2022-49217429 days apartscsi: pm8001: Fix abort all task initialization
    22Monitor

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).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Someone with local access to the system 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
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-909 · Missing Initialization of Resource

CVSS vector

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

nvd-primary

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 (10 more)

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

All records