Vulnerability Database

328,409

Total vulnerabilities in the database

CVE-2017-1000254

libcurl may read outside of a heap allocated buffer when doing FTP. When libcurl connects to an FTP server and successfully logs in (anonymous or not), it asks the server for the current directory with the PWD command. The server then responds with a 257 response containing the path, inside double quotes. The returned path name is then kept by libcurl for subsequent uses. Due to a flaw in the string parser for this directory name, a directory name passed like this but without a closing double quote would lead to libcurl not adding a trailing NUL byte to the buffer holding the name. When libcurl would then later access the string, it could read beyond the allocated heap buffer and crash or wrongly access data beyond the buffer, thinking it was part of the path. A malicious server could abuse this fact and effectively prevent libcurl-based clients to work with it - the PWD command is always issued on new FTP connections and the mistake has a high chance of causing a segfault. The simple fact that this has issue remained undiscovered for this long could suggest that malformed PWD responses are rare in benign servers. We are not aware of any exploit of this flaw. This bug was introduced in commit 415d2e7cb7, March 2005. In libcurl version 7.56.0, the parser always zero terminates the string but also rejects it if not terminated properly with a final double quote.

  • Published: Oct 6, 2017
  • Updated: Nov 9, 2025
  • CVE: CVE-2017-1000254
  • Severity: Medium
  • Exploit:

CVSS v2:

  • Severity: Medium
  • Score: 5
  • AV:N/AC:L/Au:N/C:N/I:N/A:P

CWEs:

Software From Fixed in
haxx / libcurl 7.9.5 7.9.5.x
haxx / libcurl 7.9.1 7.9.1.x
haxx / libcurl 7.19.0 7.19.0.x
haxx / libcurl 7.19.6 7.19.6.x
haxx / libcurl 7.8 7.8.x
haxx / libcurl 7.9.6 7.9.6.x
haxx / libcurl 7.7.2 7.7.2.x
haxx / libcurl 7.21.2 7.21.2.x
haxx / libcurl 7.11.2 7.11.2.x
haxx / libcurl 7.37.0 7.37.0.x
haxx / libcurl 7.40.0 7.40.0.x
haxx / libcurl 7.17.1 7.17.1.x
haxx / libcurl 7.19.4 7.19.4.x
haxx / libcurl 7.30.0 7.30.0.x
haxx / libcurl 7.25.0 7.25.0.x
haxx / libcurl 7.12.0 7.12.0.x
haxx / libcurl 7.21.3 7.21.3.x
haxx / libcurl 7.16.4 7.16.4.x
haxx / libcurl 7.7.1 7.7.1.x
haxx / libcurl 7.12.3 7.12.3.x
haxx / libcurl 7.8.1 7.8.1.x
haxx / libcurl 7.33.0 7.33.0.x
haxx / libcurl 7.18.0 7.18.0.x
haxx / libcurl 7.23.0 7.23.0.x
haxx / libcurl 7.19.1 7.19.1.x
haxx / libcurl 7.26.0 7.26.0.x
haxx / libcurl 7.36.0 7.36.0.x
haxx / libcurl 7.9.4 7.9.4.x
haxx / libcurl 7.10.5 7.10.5.x
haxx / libcurl 7.10.2 7.10.2.x
haxx / libcurl 7.15.2 7.15.2.x
haxx / libcurl 7.16.0 7.16.0.x
haxx / libcurl 7.16.2 7.16.2.x
haxx / libcurl 7.34.0 7.34.0.x
haxx / libcurl 7.31.0 7.31.0.x
haxx / libcurl 7.15.5 7.15.5.x
haxx / libcurl 7.35.0 7.35.0.x
haxx / libcurl 7.22.0 7.22.0.x
haxx / libcurl 7.20.0 7.20.0.x
haxx / libcurl 7.7.3 7.7.3.x
haxx / libcurl 7.9.2 7.9.2.x
haxx / libcurl 7.21.0 7.21.0.x
haxx / libcurl 7.14.1 7.14.1.x
haxx / libcurl 7.28.0 7.28.0.x
haxx / libcurl 7.11.1 7.11.1.x
haxx / libcurl 7.18.2 7.18.2.x
haxx / libcurl 7.13.0 7.13.0.x
haxx / libcurl 7.21.5 7.21.5.x
haxx / libcurl 7.15.1 7.15.1.x
haxx / libcurl 7.19.3 7.19.3.x
haxx / libcurl 7.17.0 7.17.0.x
haxx / libcurl 7.24.0 7.24.0.x
haxx / libcurl 7.13.1 7.13.1.x
haxx / libcurl 7.10.8 7.10.8.x
haxx / libcurl 7.27.0 7.27.0.x
haxx / libcurl 7.9 7.9.x
haxx / libcurl 7.15.3 7.15.3.x
haxx / libcurl 7.19.7 7.19.7.x
haxx / libcurl 7.12.1 7.12.1.x
haxx / libcurl 7.10.6 7.10.6.x
haxx / libcurl 7.42.1 7.42.1.x
haxx / libcurl 7.10.3 7.10.3.x
haxx / libcurl 7.41.0 7.41.0.x
haxx / libcurl 7.23.1 7.23.1.x
haxx / libcurl 7.21.6 7.21.6.x
haxx / libcurl 7.19.5 7.19.5.x
haxx / libcurl 7.9.7 7.9.7.x
haxx / libcurl 7.42.0 7.42.0.x
haxx / libcurl 7.14.0 7.14.0.x
haxx / libcurl 7.10 7.10.x
haxx / libcurl 7.21.7 7.21.7.x
haxx / libcurl 7.21.1 7.21.1.x
haxx / libcurl 7.38.0 7.38.0.x
haxx / libcurl 7.10.4 7.10.4.x
haxx / libcurl 7.16.3 7.16.3.x
haxx / libcurl 7.9.3 7.9.3.x
haxx / libcurl 7.13.2 7.13.2.x
haxx / libcurl 7.15.4 7.15.4.x
haxx / libcurl 7.20.1 7.20.1.x
haxx / libcurl 7.11.0 7.11.0.x
haxx / libcurl 7.16.1 7.16.1.x
haxx / libcurl 7.32.0 7.32.0.x
haxx / libcurl 7.29.0 7.29.0.x
haxx / libcurl 7.7 7.7.x
haxx / libcurl 7.10.1 7.10.1.x
haxx / libcurl 7.37.1 7.37.1.x
haxx / libcurl 7.18.1 7.18.1.x
haxx / libcurl 7.10.7 7.10.7.x
haxx / libcurl 7.9.8 7.9.8.x
haxx / libcurl 7.28.1 7.28.1.x
haxx / libcurl 7.12.2 7.12.2.x
haxx / libcurl 7.39 7.39.x
haxx / libcurl 7.15.0 7.15.0.x
haxx / libcurl 7.21.4 7.21.4.x
haxx / libcurl 7.19.2 7.19.2.x
haxx / libcurl 7.52.0 7.52.0.x
haxx / libcurl 7.52.1 7.52.1.x
haxx / libcurl 7.53.0 7.53.0.x
haxx / libcurl 7.53.1 7.53.1.x
haxx / libcurl 7.54.0 7.54.0.x
haxx / libcurl 7.54.1 7.54.1.x
haxx / libcurl 7.50.3 7.50.3.x
haxx / libcurl 7.51.0 7.51.0.x
haxx / libcurl 7.43.0 7.43.0.x
haxx / libcurl 7.44.0 7.44.0.x
haxx / libcurl 7.45.0 7.45.0.x
haxx / libcurl 7.46.0 7.46.0.x
haxx / libcurl 7.47.0 7.47.0.x
haxx / libcurl 7.47.1 7.47.1.x
haxx / libcurl 7.48.0 7.48.0.x
haxx / libcurl 7.49.0 7.49.0.x
haxx / libcurl 7.49.1 7.49.1.x
haxx / libcurl 7.50.0 7.50.0.x
haxx / libcurl 7.50.1 7.50.1.x
haxx / libcurl 7.50.2 7.50.2.x
haxx / libcurl 7.55.1 7.55.1.x
haxx / libcurl 7.55.0 7.55.0.x

Frequently Asked Questions

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.