Vulnerability Snapshot
CVE-2026-43186 is rated CRITICAL — exploitation is trivial or already observed in the wild and impact is severe. Patch immediately, not on the next maintenance window.
Affected technology: linux_kernel.
Executive Summary
In the Linux kernel, the following vulnerability has been resolved:
ipv6: ioam: fix heap buffer overflow in __ioam6_fill_trace_data()
On the receive path, __ioam6_fill_trace_data() uses trace->nodelen
to decide how much data to write for each node. It trusts this field
as-is from the incoming packet, with no consistency check against
trace->type (the 24-bit field that tells which data items are
present). A crafted packet can set nodelen=0 while setting type bits
0-21, causing the function to write ~100 bytes past the allocated
region (into skb_shared_info), which corrupts adjacent heap memory
and leads to a kernel panic.
Add a shared helper ioam6_trace_compute_nodelen() in ioam6.c to
derive the expected nodelen from the type field, and use it:
- in ioam6_iptunnel.c (send path, existing validation) to replace
the open-coded computation;
- in exthdrs.c (receive path, ipv6_hop_ioam) to drop packets whose
nodelen is inconsistent with the type field, before any data is
w
Why It Matters
CVE-2026-43186 is rated CRITICAL severity, requiring immediate attention from security teams.
CVSS Base Score: 9.8/10
Affected Technologies
Vendors: linux
Products: linux_kernel
🛡️What Defenders Should Check
Use Vulnios to continuously monitor your exposure to CVE-2026-43186 and similar vulnerabilities.
References & Sources
How Vulnios Detects This
Vulnios scans for this vulnerability using Trivy and Grype for CVE matching against your container images and OS package manifests. Run a scan against your environment to see whether you are exposed; findings are linked back to the original CVE record so triage starts with the patch path already known.
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Affected Products
Sources
Related Threat Alerts
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Frequently Asked Questions
What is CVE-2026-43186?
CVE-2026-43186 is a critical-severity vulnerability tracked under the Common Vulnerabilities and Exposures program. In the Linux kernel, the following vulnerability has been resolved:
ipv6: ioam: fix heap buffer overflow in __ioam6_fill_trace_data()
On the receive path, __ioam6_fill_trace_data() uses trace->nodel
Am I affected?
Check whether your environment runs linux_kernel. If you operate any of those, treat yourself as in scope until you have evidence otherwise. A Vulnios scan will identify the exact assets carrying the affected version.
How urgent is the response?
Critical: do not wait for your normal patch cycle. Verify exposure today, apply the vendor patch immediately, and add detection rules for any post-exploit indicators.
How do I remediate?
Apply the vendor patch listed in the upstream advisory linked under Sources. If the patch is not yet available, follow the vendor-supplied workaround (often a config flag or feature disable) and add detections for the published exploit pattern in your SIEM. Re-scan after the patch lands to confirm the finding clears.
Where can I track exploitation activity?
Watch CISA's Known Exploited Vulnerabilities catalog for CVE-2026-43186. Cross-reference with public exploit databases and your own SIEM/IDS for indicator-of-compromise patterns. Vulnios tracks KEV status automatically and surfaces it on the asset findings view.
How does Vulnios help with this?
Vulnios continuously cross-references your asset inventory against the live CVE feed (NVD, vendor advisories, CISA KEV, and curated OSINT). When a new CVE matches your environment, you get a prioritized finding with the severity, KEV status, exploit-prediction (EPSS), and a direct path to the vendor patch. You can start a free scan from the homepage.
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