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-2023-27533

CVE-2023-27533HIGH

n/a https://github.com/curl/curl — A vulnerability in input validation exists in curl <8.0 during communication using the TELNET protocol may allow an attacker to pass on m…

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   L   N   R  U  H  H  H    8.8   .0216   81.9     —

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-2023-27533 (https://github.com/curl/curl). Public exploit reference added.
  Oct 14  RESCORED — CVE-2023-27533 (https://github.com/curl/curl). CVSS 9.8 → 8.8 (NVD).

CWE-74, CWE-75 · CNA: hackerone · CVSS v3.1 · 7 references · NVD status: Modified

Description

A vulnerability in input validation exists in curl <8.0 during communication using the TELNET protocol may allow an attacker to pass on maliciously crafted user name and "telnet options" during server negotiation. The lack of proper input scrubbing allows an attacker to send content or perform option negotiation without the application's intent. This vulnerability could be exploited if an application allows user input, thereby enabling attackers to execute arbitrary code on the system.

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-2023-27533 (https://github.com/curl/curl). Public exploit reference added.
October 14, 2026	RESCORED	RESCORED — CVE-2023-27533 (https://github.com/curl/curl). CVSS 9.8 → 8.8 (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-74 · CWE-75

References (7)

https://cert-portal.siemens.com/productcert/html/ssa-398330.html
https://cert-portal.siemens.com/productcert/html/ssa-943925.html
https://hackerone.com/reports/1891474 [Exploit, Third Party Advisory]
https://lists.debian.org/debian-lts-announce/2023/04/msg00025.html [Mailing List]
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-20230420-0011/ [Third Party Advisory]

Authoritative record: CVE-2023-27533 at cve.org

Weaknesses: CWE-74 · CWE-75

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2023-27533 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.