Windows LDAP Null Pointer Dereference Denial of Service
CVE-2026-21243 is a denial-of-service vulnerability in Windows LDAP (Lightweight Directory Access Protocol). The issue is described as a null pointer dereference in the Windows LDAP component that can be triggered by an unauthorized attacker over the network. Based on the available information, successful exploitation causes the vulnerable LDAP service or associated process to dereference a null pointer and crash, resulting in service disruption. No additional public detail about the specific vulnerable function or code path is provided in the supplied content.
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Impact, mitigation & remediation
What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.
Impact
What an attacker gets, and what they’ve been doing with it.
Mitigation
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Remediation
Patch, then assume compromise.
Exploits
No public exploits tracked yet. Mallory keeps watching.
No public exploit code observed for this vulnerability.
Affected products & vendors
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
7 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A denial-of-service vulnerability affecting Windows LDAP.
A denial of service vulnerability in Windows LDAP (no additional details provided in the content).
A denial-of-service vulnerability in Windows LDAP.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.