CVE-2021-28546

MEDIUMNVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.5 under NVD CVSS v3. EPSS exploit probability: 1.4%, top 30% of all CVEs by exploit prediction. 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
6.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 1%CVSS: 6.5Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Acrobat Reader DC versions versions 2020.013.20074 (and earlier), 2020.001.30018 (and earlier) and 2017.011.30188 (and earlier) are missing support for an integrity check. An unauthenticated attacker could leverage this vulnerability to modify content in a certified PDF without invalidating the certification. Exploitation of this issue requires user interaction in that a victim must open the tampered file.

CVSS v3
6.5
EG Score
6.5(medium)
EPSS
70.0%
KEV
Not listed

Published

April 1, 2021

Last Modified

November 21, 2024

References (2)

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 12× in last 7d / 46× 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.

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

Frequently asked(5)

What is CVE-2021-28546?
CVE-2021-28546 is a medium vulnerability published on April 1, 2021. Acrobat Reader DC versions versions 2020.013.20074 (and earlier), 2020.001.30018 (and earlier) and 2017.011.30188 (and earlier) are missing support for an integrity check. An unauthenticated attacker could leverage this vulnerability to modify content in a certified PDF without invalidating the…
When was CVE-2021-28546 disclosed?
CVE-2021-28546 was first published in the National Vulnerability Database on April 1, 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-2021-28546 actively exploited?
CVE-2021-28546 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 70.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-28546?
CVE-2021-28546 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2021-28546?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-28546, 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.

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