CVE-2021-31810

What it is

An issue was discovered in Ruby through 2.6.7, 2.7.x through 2.7.3, and 3.x through 3.0.1. A malicious FTP server can use the PASV response to trick Net::FTP into connecting back to a given IP address and port. This potentially makes curl extract information about services that are otherwise private and not disclosed (e.g., the attacker can conduct port scans and service banner extractions).

At a glance

Exploitability

Can be exploited over the network without logging in. Limited direct impact.

Exploit odds

3.0% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2021-07-13 13:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 03:52 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 3.0% in the next 30 days (EPSS).
• Severity: 5.8 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2021-07-13 13:15 UTC

Last modified

2026-06-17 03:52 UTC

Exploit probability

3.0% · EPSS, next 30 days

Record status

Modified

Affected

• ruby-lang Ruby ≤ 2.6.7
• ruby-lang Ruby ≤ 2.7.3
• ruby-lang Ruby ≤ 3.0.1
• Debian Linux 9.0
• Oracle Jd Edwards Enterpriseone Tools < 9.2.6.1

Attack profile CVSS 3.1 · 5.8

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Changed

Confidentiality

Low

Integrity

None

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-31810.md and follow it. Check whether this project is affected by CVE-2021-31810. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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