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-2023-27538

CVE-2023-27538MEDIUM

n/a https://github.com/curl/curl — An authentication bypass vulnerability exists in libcurl prior to v8.0.0 where it reuses a previously established SSH connection despite …

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   L   L   L   N  U  H  N  N    5.5   .0145   72.9     —

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-2023-27538 (https://github.com/curl/curl). Public exploit reference added.
  Oct 14  RESCORED — CVE-2023-27538 (https://github.com/curl/curl). CVSS 7.7 → 5.5 (NVD).

CWE-287, CWE-305 · CNA: hackerone · CVSS v3.1 · 7 references · NVD status: Modified

Description

An authentication bypass vulnerability exists in libcurl prior to v8.0.0 where it reuses a previously established SSH connection despite the fact that an SSH option was modified, which should have prevented reuse. libcurl maintains a pool of previously used connections to reuse them for subsequent transfers if the configurations match. However, two SSH settings were omitted from the configuration check, allowing them to match easily, potentially leading to the reuse of an inappropriate connection.

Lifecycle

Complete event history — 4 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-2023-27538 (https://github.com/curl/curl). Public exploit reference added.
October 14, 2026	RESCORED	RESCORED — CVE-2023-27538 (https://github.com/curl/curl). CVSS 7.7 → 5.5 (NVD).

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 (7)

https://cert-portal.siemens.com/productcert/html/ssa-077170.html
https://cert-portal.siemens.com/productcert/html/ssa-398330.html
https://cert-portal.siemens.com/productcert/html/ssa-943925.html
https://hackerone.com/reports/1898475 [Exploit, Third Party Advisory]
https://lists.debian.org/debian-lts-announce/2023/04/msg00025.html [Mailing List]
https://security.gentoo.org/glsa/202310-12 [Third Party Advisory]
https://security.netapp.com/advisory/ntap-20230420-0010/ [Third Party Advisory]

Authoritative record: CVE-2023-27538 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-2023-27538 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.