CVE-2021-47734

HIGHNVD 7.85.5▼
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory (severity: HIGH) published 2025-12-23. NVD baseline CVSS 7.8; sources differ by 2.3.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Elevated
7.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 1%CVSS: 7.8Exploit: NoneExposed: 0

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

CMSimple 5.4 contains an authenticated local file inclusion vulnerability that allows remote attackers to manipulate PHP session files and execute arbitrary code. Attackers can leverage the vulnerability by changing the functions file path and uploading malicious PHP code through session file upload mechanisms.

CVSS v3
7.8
EG Score
5.5(medium)
EPSS
50.2%
KEV
Not listed

Published

December 23, 2025

Last Modified

January 5, 2026

References (3)

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× 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 14:06 UTCEPSS rescore
  2. 2026-07-21 15:22 UTCEPSS rescore
  3. 2026-07-21 15:22 UTCEPSS rescore
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  14. 2026-07-13 22:27 UTCEPSS rescore
  15. 2026-07-13 06:11 UTCEPSS rescore
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  17. 2026-07-12 05:44 UTCEPSS rescore
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  19. 2026-07-09 19:07 UTCEPSS rescore
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  21. 2026-07-08 15:12 UTCEPSS rescore
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  1. 2026-07-06 02:21 UTCEPSS rescore
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  3. 2026-07-05 02:28 UTCEPSS rescore
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  5. 2026-07-04 06:29 UTCEPSS rescore
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  7. 2026-07-01 15:04 UTCEPSS rescore
  8. 2026-06-30 23:20 UTCEPSS rescore
  9. 2026-06-29 14:04 UTCEPSS rescore
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  11. 2026-06-28 14:05 UTCEPSS rescore
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  14. 2026-06-27 03:07 UTCEPSS rescore
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  16. 2026-06-25 13:48 UTCEPSS rescore
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  18. 2026-06-24 14:03 UTCEPSS rescore
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  20. 2026-06-23 21:31 UTCEPSS rescore
  21. 2026-06-23 21:31 UTCEPSS rescore
  22. 2026-06-22 14:24 UTCEPSS rescore
  23. 2026-06-21 14:55 UTCEPSS rescore
  24. 2026-06-21 01:58 UTCEPSS rescore
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  26. 2026-06-19 19:24 UTCEPSS rescore
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  28. 2026-06-18 17:51 UTCEPSS rescore
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  36. 2026-06-13 22:58 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
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  44. 2026-06-08 14:15 UTCEPSS rescore
  45. 2026-06-07 15:23 UTCEPSS rescore
  46. 2026-06-07 15:23 UTCEPSS rescore
  47. 2026-06-06 13:46 UTCEPSS rescore
  48. 2026-06-06 13:46 UTCEPSS rescore
  49. 2026-06-05 22:45 UTCEPSS rescore
  50. 2026-06-05 22:45 UTCEPSS rescore
  51. 2026-06-05 06:09 UTCEPSS rescore
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  53. 2026-06-04 13:11 UTCEPSS rescore
  54. 2026-06-04 13:10 UTCEPSS rescore
  55. 2026-06-02 20:11 UTCEPSS rescore
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  59. 2026-05-31 22:29 UTCEPSS rescore
  60. 2026-05-31 00:15 UTCEPSS rescore
  61. 2026-05-31 00:15 UTCEPSS rescore
  62. 2026-05-29 17:05 UTCEG score recompute
  63. 2026-05-29 17:04 UTCGHSA enrichment
  64. 2026-05-29 13:42 UTCEPSS rescore

Frequently asked(5)

What is CVE-2021-47734?
CVE-2021-47734 is a high vulnerability published on December 23, 2025. CMSimple 5.4 contains an authenticated local file inclusion vulnerability that allows remote attackers to manipulate PHP session files and execute arbitrary code. Attackers can leverage the vulnerability by changing the functions file path and uploading malicious PHP code through session file…
When was CVE-2021-47734 disclosed?
CVE-2021-47734 was first published in the National Vulnerability Database on December 23, 2025, with the most recent update on January 5, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-47734 actively exploited?
CVE-2021-47734 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 50.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-47734?
CVE-2021-47734 has a CVSS v3 base score of 7.8 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 5.5.
How do I remediate CVE-2021-47734?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-47734, 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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