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).
CVE-2021-31810
Score 5.8 from GitHub Security Advisory published 2022-05-24. NVD baseline CVSS 5.8; sources differ by 0.0.
- Lower severity and no public exploit yet
A fix is available — apply it.
- CVSS v3
- 5.8
- EG Score
- 5.8(medium)
- EG Risk
- —
- EPSS
- 86.2%
- KEV
- Not listed
Published
July 13, 2021
Last Modified
November 21, 2024
References (16)
- cve@mitrehttps://hackerone.com/reports/1145454
- cve@mitrehttps://lists.debian.org/debian-lts-announce/2021/10/msg00009.html
- cve@mitrehttps://lists.debian.org/debian-lts-announce/2023/04/msg00033.html
- cve@mitrehttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MWXHK5UUHVSHF7HTHMX6JY3WXDVNIHSL/
- cve@mitrehttps://security.gentoo.org/glsa/202401-27
- cve@mitrehttps://security.netapp.com/advisory/ntap-20210917-0001/
- cve@mitrehttps://www.oracle.com/security-alerts/cpuapr2022.html
- cve@mitrehttps://www.ruby-lang.org/en/news/2021/07/07/trusting-pasv-responses-in-net-ftp/
- af854a3a-2127-422b-91ae-364da2661108https://hackerone.com/reports/1145454
- af854a3a-2127-422b-91ae-364da2661108https://lists.debian.org/debian-lts-announce/2021/10/msg00009.html
- af854a3a-2127-422b-91ae-364da2661108https://lists.debian.org/debian-lts-announce/2023/04/msg00033.html
- af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MWXHK5UUHVSHF7HTHMX6JY3WXDVNIHSL/
- af854a3a-2127-422b-91ae-364da2661108https://security.gentoo.org/glsa/202401-27
- af854a3a-2127-422b-91ae-364da2661108https://security.netapp.com/advisory/ntap-20210917-0001/
- af854a3a-2127-422b-91ae-364da2661108https://www.oracle.com/security-alerts/cpuapr2022.html
Vendor Advisories for CVE-2021-31810(8)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
- RHSA-2026:8838Red Hat Product SecurityMedium
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
- RHSA-2026:7307Red Hat Product SecurityMedium
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
- RHSA-2026:7305Red Hat Product SecurityMedium
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
- RHSA-2022:0708Red Hat Product SecurityHigh
Red Hat Security Advisory: rh-ruby26-ruby security, bug fix, and enhancement update
- RHSA-2022:0582Red Hat Product SecurityHigh
Red Hat Security Advisory: ruby:2.6 security update
- RHSA-2022:0581Red Hat Product SecurityHigh
Red Hat Security Advisory: ruby:2.6 security update
- RHSA-2021:3982Red Hat Product SecurityHigh
Red Hat Security Advisory: rh-ruby30-ruby security update
- RHSA-2021:3559Red Hat Product SecurityHigh
Red Hat Security Advisory: rh-ruby27-ruby security update
Patch Availability(13)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| ubuntu | ruby2.7-doc (2.7.0-5ubuntu1.5) @ focal | 2026-05-26 | ubuntu |
| redhat | ruby4-0-main-4.0.0-33.3.hum1 | 2026-04-17 | redhat |
| redhat | ruby3-4-main-3.4.8-31.1.hum1 | 2026-04-09 | redhat |
| redhat | ruby3-3-main-3.3.10-23.1.hum1 | 2026-04-09 | redhat |
| redhat | rh-ruby26-ruby-0:2.6.9-120.el7 | 2022-02-28 | redhat |
| redhat | ruby:2.5-8050020220216195847.c5368500 | 2022-02-24 | redhat |
| redhat | ruby:2.6-8020020220201131207.4cda2c84 | 2022-02-21 | redhat |
| redhat | ruby:2.6-8010020220201152941.c27ad7f8 | 2022-02-21 | redhat |
| redhat | ruby:2.6-8040020220131135901.522a0ee4 | 2022-02-16 | redhat |
| redhat | ruby:2.6-8050020211215144356.c5368500 | 2022-02-16 | redhat |
| redhat | rh-ruby30-ruby-0:3.0.2-148.el7 | 2021-10-25 | redhat |
| redhat | rh-ruby27-ruby-0:2.7.4-130.el7 | 2021-09-20 | redhat |
| redhat | ruby:2.7-8040020210728141159.522a0ee4 | 2021-08-05 | redhat |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Additional Vendor Advisories
(5)
Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.
Data Freshness Timeline
(refreshed 14× in last 7d / 44× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-22 22:47 UTCEG score recompute
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Frequently asked(5)
What is CVE-2021-31810?
When was CVE-2021-31810 disclosed?
Is CVE-2021-31810 actively exploited?
What is the CVSS score of CVE-2021-31810?
How do I remediate CVE-2021-31810?
Dependency Blast Radius
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