CVE-2021-28965

HIGHNVD 7.57.5—

7.5

The REXML gem before 3.2.5 in Ruby before 2.6.7, 2.7.x before 2.7.3, and 3.x before 3.0.1 does not properly address XML round-trip issues. An incorrect document can be produced after parsing and serializing.

CVSS v3: 7.5
EG Score: 7.5(medium)
EPSS: 69.0%
KEV: Not listed

Published

April 21, 2021

Last Modified

November 21, 2024

References (6)

cve@mitrehttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WTVFTLFVCSUE5CXHINJEUCKSHU4SWDMT/
cve@mitrehttps://security.netapp.com/advisory/ntap-20210528-0003/
cve@mitrehttps://www.ruby-lang.org/en/news/2021/04/05/xml-round-trip-vulnerability-in-rexml-cve-2021-28965/
af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WTVFTLFVCSUE5CXHINJEUCKSHU4SWDMT/
af854a3a-2127-422b-91ae-364da2661108https://security.netapp.com/advisory/ntap-20210528-0003/
af854a3a-2127-422b-91ae-364da2661108https://www.ruby-lang.org/en/news/2021/04/05/xml-round-trip-vulnerability-in-rexml-cve-2021-28965/

Patch Availability(13)

Vendor / Ecosystem	Fixed in / Patch	Released	Source
ubuntu	ruby2.7-doc (2.7.2-4ubuntu1.1) @ hirsute	2026-05-26	ubuntu
ubuntu	ruby2.3-tcltk (2.3.1-2~ubuntu16.04.16) @ xenial	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	ruby:2.6-8010020220201152941.c27ad7f8	2022-02-21	redhat
redhat	ruby:2.6-8020020220201131207.4cda2c84	2022-02-21	redhat
redhat	ruby:2.6-8040020210430142949.522a0ee4	2021-06-29	redhat
redhat	ruby:2.7-8040020210421133318.522a0ee4	2021-06-29	redhat
redhat	ruby:2.5-8040020200923213910.522a0ee4	2021-06-29	redhat
redhat	rh-ruby27-ruby-0:2.7.3-129.el7	2021-06-03	redhat
redhat	rh-ruby26-ruby-0:2.6.7-119.el7	2021-06-03	redhat
redhat	rh-ruby25-ruby-0:2.5.9-9.el7	2021-05-26	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.

Affected Packages

(1 across 1 ecosystem)

RubyGems(1)

Package	Vulnerable range	Fixed in	Dependents
rexml	3.1.7.3 ... 3.2.4 (9 versions)	3.2.5	—

All Vendor Advisories

(14)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 7× in last 7d / 7× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-05-27 13:39 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-26 18:06 UTCEG score recompute
2026-05-26 18:06 UTCVendor advisory
2026-05-26 13:42 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch

Frequently asked(5)

What is CVE-2021-28965?

CVE-2021-28965 is a high vulnerability published on April 21, 2021. The REXML gem before 3.2.5 in Ruby before 2.6.7, 2.7.x before 2.7.3, and 3.x before 3.0.1 does not properly address XML round-trip issues. An incorrect document can be produced after parsing and serializing.

When was CVE-2021-28965 disclosed?

CVE-2021-28965 was first published in the National Vulnerability Database on April 21, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-28965 actively exploited?

CVE-2021-28965 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 69.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-28965?

CVE-2021-28965 has a CVSS v3 base score of 7.5 (NVD).

How do I remediate CVE-2021-28965?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-28965, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-28965

Explore →

Is Your Infrastructure Affected by CVE-2021-28965?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs

CVE-2021-28965

📅 Published

🔄 Last Modified

🔗 References (6)