CVE-2023-51771

CRITICALNVD 9.89.8—Elevated

9.8

In MicroHttpServer (aka Micro HTTP Server) through a8ab029, _ParseHeader in lib/server.c allows a one-byte recv buffer overflow via a long URI.

CVSS v3: 9.8
EG Score: 9.8(medium)
EPSS: 29.4%
KEV: Not listed

Published

December 25, 2023

Last Modified

April 23, 2025

Advisory Details (2)

Auto-updated May 24, 2026

🔬 Proof of concept available. No patch confirmed yet.

generic

GitHub - starnight/MicroHttpServer at a8ab029c9a26a4c9f26b9d8a2757b8299aaff120 · GitHub

https://github.com/starnight/MicroHttpServer/tree/a8ab029c9a26a4c9f26b9d8a2757b8299aaff120

generic🟡 PoC Available

Remote buffer overflow in lib/server.c · Issue #8 · starnight/MicroHttpServer · GitHub

https://github.com/starnight/MicroHttpServer/issues/8

Weakness Classification(1)

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

CWE-120Buffer Copy without Checking Size (Classic Buffer Overflow)

Data Freshness Timeline

(refreshed 18× in last 7d / 20× 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.

2026-06-06 13:46 UTCepss_batch
2026-06-06 13:46 UTCepss_batch
2026-06-05 22:46 UTCepss_batch
2026-06-05 22:46 UTCepss_batch
2026-06-05 06:09 UTCepss_batch
2026-06-05 06:09 UTCepss_batch
2026-06-05 06:09 UTCepss_batch
2026-06-04 13:11 UTCepss_batch
2026-06-04 13:11 UTCepss_batch
2026-06-04 13:11 UTCepss_batch
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 00:15 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-29 13:43 UTCepss_batch
2026-05-28 13:44 UTCepss_batch

Frequently asked(5)

What is CVE-2023-51771?

CVE-2023-51771 is a critical vulnerability published on December 25, 2023. In MicroHttpServer (aka Micro HTTP Server) through a8ab029, _ParseHeader in lib/server.c allows a one-byte recv buffer overflow via a long URI.

When was CVE-2023-51771 disclosed?

CVE-2023-51771 was first published in the National Vulnerability Database on December 25, 2023, with the most recent update on April 23, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2023-51771 actively exploited?

CVE-2023-51771 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 29.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2023-51771?

CVE-2023-51771 has a CVSS v3 base score of 9.8 (NVD).

How do I remediate CVE-2023-51771?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2023-51771, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2023-51771

Explore →

Is Your Infrastructure Affected by CVE-2023-51771?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs

CVE-2023-51771

📅 Published

🔄 Last Modified

📋 Advisory Details (2)