CVE-2026-43099
HighIn 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".
CVSS 3.1 score
7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness type
CWE-476CVE-2026-43099 is a NULL Pointer Dereference vulnerability
What is NULL Pointer Dereference?
The product dereferences a pointer that it expects to be valid but is NULL, typically causing a crash. Learn more on MITRE CWE
Affected versions
Linux kernel versions
5.13
and later are affected. Fixed in
5.15.209,
6.1.175,
6.6.136,
6.12.83,
6.18.24,
6.19.14,
7.0
and their respective stable series.
References
The following references provide additional information about CVE-2026-43099 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.
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PatchKernel patch commithttps://git.kernel.org/stable/c/0f21bc261e60f0c696c58841c4873ff77ed83673
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PatchKernel patch commithttps://git.kernel.org/stable/c/47a8bf52156ac7e7a581eca31c1f964ba4258d4d
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PatchKernel patch commithttps://git.kernel.org/stable/c/5b9911582d441f72fe6ccb15ffe3303bbc07f6f5
Frequently asked questions
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What is CVE-2026-43099?
CVE-2026-43099 is a High severity Linux kernel vulnerability with a CVSS score of 7.5 out of 10 , classified as a NULL Pointer Dereference flaw (CWE-476) . It affects Linux kernel versions from 5.13 onward and has been patched in 5.15.209, 6.1.175, 6.6.136 and others. CVE-2026-43099 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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What is the CVSS score for CVE-2026-43099?
CVE-2026-43099 has a CVSS score of 7.5 out of 10, rated High severity (CVSS 3.1). The vector string is
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. -
Is there a patch available for CVE-2026-43099?
Yes — CVE-2026-43099 has been patched. Fixed versions include 5.15.209, 6.1.175, 6.6.136 and others. If you are running Linux kernel 5.13 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-43099 actively exploited?
No — CVE-2026-43099 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.
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What is NULL Pointer Dereference (CWE-476)?
The product dereferences a pointer that it expects to be valid but is NULL, typically causing a crash. View CWE-476 on MITRE CWE →