CVE-2021-28965

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 5.1% (92nd percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 5.1%CVSS: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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
7.5HIGHmedium confidence
EG Risk
40
EG Risk 40/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity75% × 45%
Exploitation5% × 40%
Automatability30% × 15%
CISA SSVC: Track at low or medium mission impact; Track or Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
5.1%
EPSS %ILE
92nd
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track or Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

April 21, 2021

Last Modified

November 21, 2024

References (6)

Vendor Advisories for CVE-2021-28965(12)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(13)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubunturuby2.7-doc (2.7.2-4ubuntu1.1) @ hirsute2026-05-26ubuntu
ubunturuby2.3-tcltk (2.3.1-2~ubuntu16.04.16) @ xenial2026-05-26ubuntu
redhatruby4-0-main-4.0.0-33.3.hum12026-04-17redhat
redhatruby3-4-main-3.4.8-31.1.hum12026-04-09redhat
redhatruby3-3-main-3.3.10-23.1.hum12026-04-09redhat
redhatruby:2.6-8010020220201152941.c27ad7f82022-02-21redhat
redhatruby:2.6-8020020220201131207.4cda2c842022-02-21redhat
redhatruby:2.6-8040020210430142949.522a0ee42021-06-29redhat
redhatruby:2.7-8040020210421133318.522a0ee42021-06-29redhat
redhatruby:2.5-8040020200923213910.522a0ee42021-06-29redhat
redhatrh-ruby27-ruby-0:2.7.3-129.el72021-06-03redhat
redhatrh-ruby26-ruby-0:2.6.7-119.el72021-06-03redhat
redhatrh-ruby25-ruby-0:2.5.9-9.el72021-05-26redhat

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

(18 across 18 ecosystems)
Alpine:v3.10(1)
PackageVulnerable rangeFix by version rangeDependents
ruby—
  • 2.7.0 up to 2.5.9-r0: fixed in 2.5.9-r0
—
Alpine:v3.11(1)
PackageVulnerable rangeFix by version rangeDependents
ruby—
  • 2.7.0 up to 2.6.7-r0: fixed in 2.6.7-r0
—
Alpine:v3.12(1)
PackageVulnerable rangeFix by version rangeDependents
ruby—
  • 2.7.0 up to 2.7.3-r0: fixed in 2.7.3-r0
—
Alpine:v3.13(1)
PackageVulnerable rangeFix by version rangeDependents
ruby—
  • 2.7.0 up to 2.7.3-r0: fixed in 2.7.3-r0
—
Alpine:v3.14(1)
PackageVulnerable rangeFix by version rangeDependents
ruby—
  • 2.7.0 up to 2.7.3-r0: fixed in 2.7.3-r0
—
Alpine:v3.15(1)
PackageVulnerable rangeFix by version rangeDependents
ruby—
  • 2.7.0 up to 2.7.3-r0: fixed in 2.7.3-r0
—
Alpine:v3.16(1)
PackageVulnerable rangeFix by version rangeDependents
ruby—
  • 2.7.0 up to 2.7.3-r0: fixed in 2.7.3-r0
—
Alpine:v3.17(1)
PackageVulnerable rangeFix by version rangeDependents
ruby—
  • 2.7.0 up to 2.7.3-r0: fixed in 2.7.3-r0
—
Alpine:v3.18(1)
PackageVulnerable rangeFix by version rangeDependents
ruby—
  • 2.7.0 up to 2.7.3-r0: fixed in 2.7.3-r0
—
Alpine:v3.19(1)
PackageVulnerable rangeFix by version rangeDependents
ruby—
  • 2.7.0 up to 2.7.3-r0: fixed in 2.7.3-r0
—
Alpine:v3.20(1)
PackageVulnerable rangeFix by version rangeDependents
ruby—
  • 2.7.0 up to 2.7.3-r0: fixed in 2.7.3-r0
—
Alpine:v3.21(1)
PackageVulnerable rangeFix by version rangeDependents
ruby—
  • 2.7.0 up to 2.7.3-r0: fixed in 2.7.3-r0
—
Alpine:v3.22(1)
PackageVulnerable rangeFix by version rangeDependents
ruby—
  • 2.7.0 up to 2.7.3-r0: fixed in 2.7.3-r0
—
Alpine:v3.23(1)
PackageVulnerable rangeFix by version rangeDependents
ruby—
  • 2.7.0 up to 2.7.3-r0: fixed in 2.7.3-r0
—
Alpine:v3.24(1)
PackageVulnerable rangeFix by version rangeDependents
ruby—
  • 2.7.0 up to 2.7.3-r0: fixed in 2.7.3-r0
—
Debian:10(1)
PackageVulnerable rangeFix by version rangeDependents
ruby2.52.5.5-3, 2.5.5-3+deb10u1, 2.5.5-3+deb10u2, 2.5.5-3+deb10u3
  • every version up to 2.5.5-3+deb10u4: fixed in 2.5.5-3+deb10u4
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
ruby2.7—
  • every version up to 2.7.3-1: fixed in 2.7.3-1
—
RubyGems(1)
PackageVulnerable rangeFix by version rangeDependents
rexml3.1.7.3 ... 3.2.4 (9 versions)
  • every version up to 3.2.5: fixed in 3.2.5
—

Additional Vendor Advisories

(2)

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 6× in last 7d / 32× 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.

Showing the most recent 100 of 184 total refreshes for this CVE.

  1. 2026-10-09 20:04 UTCEPSS rescore
  2. 2026-10-08 16:39 UTCEPSS rescore
  3. 2026-10-07 23:44 UTCEPSS rescore
  4. 2026-10-06 15:14 UTCEPSS rescore
  5. 2026-10-05 17:40 UTCEPSS rescore
  6. 2026-10-04 23:19 UTCEPSS rescore
  7. 2026-10-03 14:22 UTCEPSS rescore
  8. 2026-10-03 14:22 UTCEPSS rescore
  9. 2026-10-02 16:22 UTCEPSS rescore
  10. 2026-10-01 19:46 UTCEPSS rescore
  11. 2026-09-30 15:34 UTCEG score recompute
  12. 2026-09-30 15:00 UTCEPSS rescore
  13. 2026-09-29 15:15 UTCEPSS rescore
  14. 2026-09-28 13:47 UTCEPSS rescore
  15. 2026-09-27 13:41 UTCEPSS rescore
  16. 2026-09-26 15:54 UTCEPSS rescore
  17. 2026-09-26 15:54 UTCEPSS rescore
  18. 2026-09-26 04:12 UTCOSV refresh
  19. 2026-09-26 00:21 UTCEPSS rescore
  20. 2026-09-24 14:00 UTCEPSS rescore
  21. 2026-09-23 13:44 UTCEPSS rescore
  22. 2026-09-21 20:28 UTCEPSS rescore
  23. 2026-09-19 15:37 UTCEPSS rescore
  24. 2026-09-18 19:23 UTCEPSS rescore
  25. 2026-09-17 19:23 UTCEPSS rescore
Show 75 more
  1. 2026-09-17 19:23 UTCEPSS rescore
  2. 2026-09-16 14:05 UTCEPSS rescore
  3. 2026-09-15 03:06 UTCEPSS rescore
  4. 2026-09-15 03:06 UTCEPSS rescore
  5. 2026-09-12 14:57 UTCEPSS rescore
  6. 2026-09-11 14:49 UTCEPSS rescore
  7. 2026-09-11 09:33 UTCEPSS rescore
  8. 2026-09-08 21:56 UTCEPSS rescore
  9. 2026-09-07 15:58 UTCEPSS rescore
  10. 2026-09-06 19:01 UTCOSV refresh
  11. 2026-09-06 13:44 UTCEPSS rescore
  12. 2026-09-05 15:25 UTCEPSS rescore
  13. 2026-09-04 13:57 UTCEPSS rescore
  14. 2026-09-04 05:03 UTCEPSS rescore
  15. 2026-09-04 05:03 UTCEPSS rescore
  16. 2026-09-02 14:08 UTCEPSS rescore
  17. 2026-09-01 13:50 UTCEPSS rescore
  18. 2026-09-01 03:32 UTCEPSS rescore
  19. 2026-08-30 19:14 UTCEPSS rescore
  20. 2026-08-30 01:19 UTCEPSS rescore
  21. 2026-08-28 21:37 UTCEPSS rescore
  22. 2026-08-27 14:22 UTCEPSS rescore
  23. 2026-08-26 14:42 UTCEPSS rescore
  24. 2026-08-25 13:45 UTCEPSS rescore
  25. 2026-08-24 14:12 UTCEPSS rescore
  26. 2026-08-23 00:16 UTCEPSS rescore
  27. 2026-08-21 23:46 UTCEPSS rescore
  28. 2026-08-20 22:52 UTCEPSS rescore
  29. 2026-08-20 05:04 UTCOSV refresh
  30. 2026-08-19 17:01 UTCEPSS rescore
  31. 2026-08-18 13:45 UTCEPSS rescore
  32. 2026-08-17 13:44 UTCEPSS rescore
  33. 2026-08-16 14:53 UTCEPSS rescore
  34. 2026-08-16 02:11 UTCEPSS rescore
  35. 2026-08-16 02:11 UTCEPSS rescore
  36. 2026-08-15 01:27 UTCEPSS rescore
  37. 2026-08-13 21:57 UTCEPSS rescore
  38. 2026-08-12 13:47 UTCEPSS rescore
  39. 2026-08-11 13:38 UTCEPSS rescore
  40. 2026-08-09 13:43 UTCEPSS rescore
  41. 2026-08-08 16:33 UTCEPSS rescore
  42. 2026-08-07 16:23 UTCEPSS rescore
  43. 2026-08-06 13:43 UTCEPSS rescore
  44. 2026-08-05 19:14 UTCEPSS rescore
  45. 2026-08-05 00:11 UTCOSV refresh
  46. 2026-08-04 15:06 UTCEPSS rescore
  47. 2026-08-04 10:34 UTCEPSS rescore
  48. 2026-08-03 10:33 UTCEPSS rescore
  49. 2026-08-02 02:24 UTCEPSS rescore
  50. 2026-08-01 04:13 UTCEPSS rescore
  51. 2026-07-30 16:25 UTCEPSS rescore
  52. 2026-07-30 16:25 UTCEPSS rescore
  53. 2026-07-30 01:28 UTCEPSS rescore
  54. 2026-07-30 01:27 UTCEPSS rescore
  55. 2026-07-28 15:33 UTCEPSS rescore
  56. 2026-07-26 14:52 UTCEPSS rescore
  57. 2026-07-26 14:52 UTCEPSS rescore
  58. 2026-07-25 14:15 UTCEPSS rescore
  59. 2026-07-24 14:15 UTCEPSS rescore
  60. 2026-07-23 14:16 UTCEPSS rescore
  61. 2026-07-23 01:59 UTCEG score recompute
  62. 2026-07-22 22:46 UTCEG score recompute
  63. 2026-07-22 14:06 UTCEPSS rescore
  64. 2026-07-22 14:06 UTCEPSS rescore
  65. 2026-07-21 15:22 UTCEPSS rescore
  66. 2026-07-21 15:22 UTCEPSS rescore
  67. 2026-07-20 17:05 UTCEPSS rescore
  68. 2026-07-19 14:28 UTCEPSS rescore
  69. 2026-07-19 02:27 UTCEPSS rescore
  70. 2026-07-19 02:27 UTCEPSS rescore
  71. 2026-07-18 22:29 UTCOSV refresh
  72. 2026-07-18 10:02 UTCEPSS rescore
  73. 2026-07-18 10:02 UTCEPSS rescore
  74. 2026-07-16 17:00 UTCEPSS rescore
  75. 2026-07-15 16:55 UTCEPSS rescore

Related CVEs(same product + same vendor)

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 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 5.1% probability of exploitation in the next 30 days (92nd percentile of EPSS-scored CVEs).
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?
A fix for CVE-2021-28965 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2021-28965 are linked in the Vendor Advisories panel on this page.

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