What is CVE-2021-28965?

CVE-2021-28965 is a high-severity vulnerability in Ruby-Lang Rexml. CVSS score: 7.5/10. Published 2021-04-21.

How severe is CVE-2021-28965?

High severity. CVSS v3 base score is 7.5 out of 10.

Is CVE-2021-28965 known to be exploited?

3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Ruby-Lang Rexml

CVE-2021-28965

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.

Published 2021-04-21 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

EPSS exploit prediction

EPSS: 0.051 (92.0th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 92nd percentile — 92.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.051 · newest: 0.051 · change: 0.000

Affected products

Public proof-of-concept exploits

References

www.ruby-lang.org/en/news/2021/04/05/xml-round-trip-vulnerability-in-rexml-cve-… (Vendor Advisory)
lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
security.netapp.com/advisory/ntap-20210528-0003/ (Third Party Advisory)

Frequently asked questions

What is CVE-2021-28965?: CVE-2021-28965 is a high-severity vulnerability in Ruby-Lang Rexml. CVSS score: 7.5/10. Published 2021-04-21.
How severe is CVE-2021-28965?: High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2021-28965 known to be exploited?: 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.