How severe is CVE-2026-21525?

CVE-2026-21525 has a CVSS 3.x base score of 6.2, rated medium severity. It is exploitable over local access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-21525 being actively exploited?

Yes. CVE-2026-21525 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2026-02-10, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2026-21525?

CVE-2026-21525 primarily affects Microsoft Windows 10 1607. In total, 23 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-21525?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2026-21525 have an EU (EUVD) identifier?

Yes. CVE-2026-21525 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-7329. It is also flagged as exploited in the EUVD (since 2026-02-10).

When was CVE-2026-21525 published?

CVE-2026-21525 was published on 2026-02-10 and last updated on 2026-06-17.

CVE-2026-21525

CVE-2026-21525 is a medium-severity vulnerability in Microsoft Windows 10 1607 with a CVSS 3.x base score of 6.2. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2026-02-10). The underlying weakness is classified as CWE-476.

Key facts

Severity: Medium (CVSS 3.x base score 6.2)
EPSS exploit prediction: 5% (91st percentile)
Actively exploited: Yes — listed in CISA KEV (added 2026-02-10)
EU (EUVD) id: EUVD-2026-7329
EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2026-02-10)
Weakness: CWE-476
Affected product: Microsoft Windows 10 1607
Published: 2026-02-10
Last modified: 2026-06-17

Description

Null pointer dereference in Windows Remote Access Connection Manager allows an unauthorized attacker to deny service locally.

Frequently asked questions

What is CVE-2026-21525?: Null pointer dereference in Windows Remote Access Connection Manager allows an unauthorized attacker to deny service locally.
How severe is CVE-2026-21525?: CVE-2026-21525 has a CVSS 3.x base score of 6.2, rated medium severity. It is exploitable over local access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-21525 being actively exploited?: Yes. CVE-2026-21525 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2026-02-10, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2026-21525?: CVE-2026-21525 primarily affects Microsoft Windows 10 1607. In total, 23 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-21525?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2026-21525 have an EU (EUVD) identifier?: Yes. CVE-2026-21525 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-7329. It is also flagged as exploited in the EUVD (since 2026-02-10).
When was CVE-2026-21525 published?: CVE-2026-21525 was published on 2026-02-10 and last updated on 2026-06-17.

References

Affected products (23)

cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2022_23h2:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:*:*

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Other CWE-476 (NULL Pointer Dereference) vulnerabilities

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CVE-2010-2495 — Critical (CVSS 10.0): The pppol2tp_xmit function in drivers/net/pppol2tp.c in the L2TP implementation in the Linux kernel before 2.6.34 does…
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CVE-2026-31657 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: batman-adv: hold claim backbone gateways by…
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