Threat Intelligence / CVE / CVE-2026-33826

CVE-2026-33826 — Microsoft Windows IKE Extensions (IKEEXT)

CVSS v3.1 9.1 (CRITICAL) · EPSS 1.0% (higher than 78.1% of all scored CVEs) · Priority 7.7/10 · Published 2026-04-14

As of 2026-04-14, CVE-2026-33826 is a CRITICAL-severity vulnerability in Microsoft Windows IKE Extensions (IKEEXT), CVSS v3.1 9.1, EPSS 1.0% (78.1th percentile). Threadlinqs Intelligence links 2 tracked threat campaigns to CVE-2026-33826, most recently “Microsoft April 2026 Patch Tuesday — 163 CVEs / 88 Advisories (CVE-2026-32201 SharePoint Zero-Day Exploited In-The-Wild, CVE-2026-33825 Defender EoP Public PoC, CVE-2026-33824 IKE RCE CVSS 9.8, CVE-2026-33827 TCP/IP Wormable RCE)”.

Last updated: 2026-04-14

What is CVE-2026-33826?

A stack-based buffer overflow in the Windows IKE Extensions service (IKEEXT) allows an unauthenticated remote attacker to achieve code execution by sending a malformed IKE_SA_INIT packet. The vulnerability is in the IKEv2 negotiation parser and requires no user interaction or authentication. The network-adjacent attack vector and lack of required privileges make this a critical-severity issue with potential for wormable exploitation across enterprise VPN and IPsec infrastructure.

The record classifies CVE-2026-33826 under weakness class CWE-121. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 151 days ago.

Severity and exploitation probability

CVSS v3.1 base score
9.1 — CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS (FIRST)
1.0% probability of exploitation in the next 30 days, higher than 78.1% of all scored CVEs
CISA KEV
Not listed in the CISA Known Exploited Vulnerabilities catalog
Threadlinqs priority
7.7/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
Published
2026-04-14

Is CVE-2026-33826 being exploited?

It currently carries a trending score of 25 in the Threadlinqs vulnerability feed.

Affected products and versions

How to fix CVE-2026-33826

The record marks a vendor fix as available for CVE-2026-33826. Patch reference: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-33826. Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-33826. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.

Threat activity tracking CVE-2026-33826

2 tracked threats in the Threadlinqs corpus reference CVE-2026-33826, either in the campaign’s CVE list or as an indicator on the campaign record.

Sources

Seeded from threat-derived and not yet processed by the Threadlinqs enrichment pipeline, so blank CVSS, EPSS or KEV fields above mean NOT MEASURED rather than measured-absent.

Full detection coverage & IOCs for threats exploiting CVE-2026-33826 are available via the Threadlinqs MCP server (Purple tier). View plans →

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