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NVD / CVE Program· CNA Linux

CVE-2026-43099: ipv4: icmp: fix null-ptr-deref in icmp_build_probe()

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: 0.50% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 0f21bc261e60f0c696c58841c4873ff77ed83673, 47a8bf52156ac7e7a581eca31c1f964ba4258d4d, 5b9911582d441f72fe6ccb15ffe3303bbc07f6f5.

Low priority for now. Upgrade to Linux Linux 0f21bc261e60f0c696c58841c4873ff77ed83673, 47a8bf52156ac7e7a581eca31c1f964ba4258d4d, 5b9911582d441f72fe6ccb15ffe3303bbc07f6f5 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: ipv4: icmp: fix null-ptr-deref in icmp_build_probe() ipv6_stub->ipv6_dev_find() may return ERR_PTR(-EAFNOSUPPORT) when the IPv6 stack is not active (CONFIG_IPV6=m and not loaded), and passing this error pointer to dev_hold() will cause a kernel crash with null-ptr-deref. Instead, silently discard the request. RFC 8335 does not appear to define a specific response for the case where an IPv6 interface identifier is syntactically valid but the implementation cannot perform the lookup at runtime, and silently dropping the request may safer than misreporting "No Such Interface".

HighCVSS 7.5 · v3.1—No exploit Fix available
Published
May 6, 2026
Updated
Oct 15, 2026
EPSS
0.5% · 42th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CNA vs NVD score

NVD
—
CNA · Linux
7.5
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-2026-43099

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 kernel5.13 and later · before 6.6.136
  • linux linux kernel6.7 and later · before 6.12.83
  • linux linux kernel6.13 and later · before 6.18.24
  • linux linux kernel6.19 and later · before 6.19.14
  • 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

    • 5.13affected
    • 6.19.14 and later · up to and including 6.19.*not affected · semver
    • 7.0 and laternot affected · original_commit_for_fix
    • d329ea5bd8845f0b196bf41b18b6173340d6e0e4 and later · before 0f21bc261e60f0c696c58841c4873ff77ed83673affected · git
    • d329ea5bd8845f0b196bf41b18b6173340d6e0e4 and later · before dc5db4db19766a61ad65d81d1f55b1c1e51ba78daffected · git
    • d329ea5bd8845f0b196bf41b18b6173340d6e0e4 and later · before 47a8bf52156ac7e7a581eca31c1f964ba4258d4daffected · git
    • d329ea5bd8845f0b196bf41b18b6173340d6e0e4 and later · before 6be325206850a0891896d38bcf83a09d8b54ec48affected · git
    • d329ea5bd8845f0b196bf41b18b6173340d6e0e4 and later · before f91b3ed9e7fa82a70511b5f6901c88379acf2964affected · git
    • d329ea5bd8845f0b196bf41b18b6173340d6e0e4 and later · before 5b9911582d441f72fe6ccb15ffe3303bbc07f6f5affected · git
    • d329ea5bd8845f0b196bf41b18b6173340d6e0e4 and later · before fde29fd9349327acc50d19a0b5f3d5a6c964dfd8affected · git

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 6.19.14-16.19.14-1

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-2026-43093May 6, 2026 · xsk: tighten UMEM headroom validation to account for tailroom and min frame
    31Monitor
  • ← EarlierCVE-2026-43094May 6, 2026 · ixgbevf: add missing negotiate_features op to Hyper-V ops table
    22Monitor
  • Later →CVE-2026-43101May 6, 2026 · ipv6: ioam: fix potential NULL dereferences in __ioam6_fill_trace_data()
    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 Linux0f21bc261e60f0c696c58841c4873ff77ed83673Vendor (CNA)
Linux Linux47a8bf52156ac7e7a581eca31c1f964ba4258d4dVendor (CNA)
Linux Linux5b9911582d441f72fe6ccb15ffe3303bbc07f6f5Vendor (CNA)
Linux Linux6be325206850a0891896d38bcf83a09d8b54ec48Vendor (CNA)
Linux Linuxdc5db4db19766a61ad65d81d1f55b1c1e51ba78dVendor (CNA)
Linux Linuxf91b3ed9e7fa82a70511b5f6901c88379acf2964Vendor (CNA)
Linux Linuxfde29fd9349327acc50d19a0b5f3d5a6c964dfd8Vendor (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.

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.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

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

Weakness class (CWE)

CWE-476 · NULL Pointer Dereference

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 (7 more)

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

All records