Reference page — cumulative record through Monday, October 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2023-27535

CVE-2023-27535MEDIUM

n/a https://github.com/curl/curl — An authentication bypass vulnerability exists in libcurl <8.0.0 in the FTP connection reuse feature that can result in wrong credentials …

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   H   N   N  U  H  N  N    5.9   .0180   78.2     —

AFFECTED
  Product                       Versions          Fixed
  https://github.com/curl/curl  Fixed in 8.0.0 –  —

TIMELINE
  Mar 2   Reserved by hackerone
  Mar 30  Published (CNA: hackerone)
  Oct 14  EXPLOIT PUBLISHED — CVE-2023-27535 (https://github.com/curl/curl). Public exploit reference added.

CWE-287, CWE-305 · CNA: hackerone · CVSS v3.1 · 8 references · NVD status: Modified

Description

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.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
March 2, 2023	Reserved	Reserved by hackerone
March 30, 2023	Published	Published (CNA: hackerone)
October 14, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2023-27535 (https://github.com/curl/curl). Public exploit reference added.

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
n/a	https://github.com/curl/curl	—	Fixed in 8.0.0	—

Weaknesses

CWE-287 · CWE-305

References (8)

https://cert-portal.siemens.com/productcert/html/ssa-398330.html
https://cert-portal.siemens.com/productcert/html/ssa-806742.html
https://cert-portal.siemens.com/productcert/html/ssa-943925.html
https://hackerone.com/reports/1892780 [Exploit, Third Party Advisory]
https://lists.debian.org/debian-lts-announce/2023/04/msg00025.html [Mailing List, Third Party Advisory]
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/36NBD5YLJXXEDZLDGNFCERWRYJQ6LAQW/ [Mailing List, Third Party Advisory]
https://security.gentoo.org/glsa/202310-12 [Third Party Advisory]
https://security.netapp.com/advisory/ntap-20230420-0010/ [Third Party Advisory]

Authoritative record: CVE-2023-27535 at cve.org

Weaknesses: CWE-287 · CWE-305

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2023-27535 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Monday, October 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.