CVE-2025-53809

MEDIUMNVD 6.56.5—Trending — 4 sources updated this week

6.5

Improper input validation in Windows Local Security Authority Subsystem Service (LSASS) allows an authorized attacker to deny service over a network.

CVSS v3: 6.5
EG Score: 6.5(medium)
EPSS: 68.6%
KEV: Not listed

Published

September 9, 2025

Last Modified

September 22, 2025

References (1)

secure@microsofthttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-53809

Vendor Advisories for CVE-2025-53809(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

CVE-2025-53809
Microsoft Security Response Center (MSRC)High
Windows Local Security Authority Subsystem Service (LSASS) Denial of Service Vulnerability

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

CWE-20Improper Input Validation

Data Freshness Timeline

(refreshed 12× in last 7d / 12× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-06-02 20:12 UTCepss_batch
2026-06-02 20:12 UTCepss_batch
2026-06-01 13:51 UTCepss_batch
2026-06-01 13:51 UTCepss_batch
2026-05-31 22:30 UTCepss_batch
2026-05-31 22:30 UTCepss_batch
2026-05-31 00:16 UTCepss_batch
2026-05-31 00:16 UTCepss_batch
2026-05-29 23:12 UTCEG score recompute
2026-05-29 23:12 UTCVendor advisory
2026-05-29 23:12 UTCGHSA enrichment
2026-05-29 13:44 UTCepss_batch

Frequently asked(5)

What is CVE-2025-53809?

CVE-2025-53809 is a medium vulnerability published on September 9, 2025. Improper input validation in Windows Local Security Authority Subsystem Service (LSASS) allows an authorized attacker to deny service over a network.

When was CVE-2025-53809 disclosed?

CVE-2025-53809 was first published in the National Vulnerability Database on September 9, 2025, with the most recent update on September 22, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2025-53809 actively exploited?

CVE-2025-53809 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 68.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2025-53809?

CVE-2025-53809 has a CVSS v3 base score of 6.5 (NVD).

How do I remediate CVE-2025-53809?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-53809, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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CVE-2025-53809

Published

Last Modified

References (1)

Vendor Advisories for CVE-2025-53809(1)

Weakness Classification(1)

Data Freshness Timeline

Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2025-53809?

Same vendor

Same CWE

CVE-2025-53809

📅 Published

🔄 Last Modified

🔗 References (1)

📣 Vendor Advisories for CVE-2025-53809(1)

Weakness Classification(1)

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2025-53809?

🔗 Related CVEs(same vendor + same CWE)

Same vendor

Same CWE

Published

Last Modified

References (1)

Vendor Advisories for CVE-2025-53809(1)

Frequently asked(5)

Related CVEs(same vendor + same CWE)