CVE-2023-27535

MEDIUMNVD 5.97.5▲
EchelonGraph scoreMEDIUM confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2023-03-30. NVD baseline CVSS 5.9; sources differ by 1.6.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 3 sources updated this weekElevated
5.9
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 2%CVSS: 5.9Exploit: NoneExposed: 0

A fix is available — apply it.

An authentication bypass vulnerability exists in libcurl <8.0.0 in the FTP connection reuse feature that can result in wrong credentials being used during subsequent transfers. Previously created connections are kept in a connection pool for reuse if they match the current setup. However, certain FTP settings such as CURLOPT_FTP_ACCOUNT, CURLOPT_FTP_ALTERNATIVE_TO_USER, CURLOPT_FTP_SSL_CCC, and CURLOPT_USE_SSL were not included in the configuration match checks, causing them to match too easily. This could lead to libcurl using the wrong credentials when performing a transfer, potentially allowing unauthorized access to sensitive information.

CVSS v3
5.9
EG Score
7.5(medium)
EG Risk
—
EPSS
73.4%
KEV
Not listed

Published

March 30, 2023

Last Modified

June 9, 2025

References (10)

Patch Availability(5)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntucurl (7.81.0-1ubuntu1.10) @ jammy2026-05-25ubuntu
ubuntucurl (7.35.0-1ubuntu2.20+esm15) @ trusty2026-05-25ubuntu
redhatcurl-0:7.61.1-22.el8_6.122024-01-25redhat
redhatcurl-0:7.61.1-30.el8_8.22023-05-16redhat
redhatcurl-0:7.76.1-23.el9_2.12023-05-09redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(2)

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

All Vendor Advisories

(6)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 14× in last 7d / 49× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 106 total refreshes for this CVE.

  1. 2026-07-22 23:08 UTCEG score recompute
  2. 2026-07-22 14:06 UTCEPSS rescore
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Frequently asked(5)

What is CVE-2023-27535?
CVE-2023-27535 is a medium vulnerability published on March 30, 2023. An authentication bypass vulnerability exists in libcurl <8.0.0 in the FTP connection reuse feature that can result in wrong credentials being used during subsequent transfers. Previously created connections are kept in a connection pool for reuse if they match the current setup. However, certain…
When was CVE-2023-27535 disclosed?
CVE-2023-27535 was first published in the National Vulnerability Database on March 30, 2023, with the most recent update on June 9, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2023-27535 actively exploited?
CVE-2023-27535 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 73.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2023-27535?
CVE-2023-27535 has a CVSS v3 base score of 5.9 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 7.5.
How do I remediate CVE-2023-27535?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2023-27535, 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.

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