CVE-2021-47964

HIGHNVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-05-15. NVD baseline CVSS 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 3 sources updated this weekElevated
8.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 8.8Exploit: Elevated riskExposed: 0

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

Schlix CMS 2.2.6-6 contains a remote code execution vulnerability that allows authenticated attackers to execute arbitrary PHP code by uploading malicious extension packages through the block manager. Attackers can upload a crafted ZIP file containing PHP code in the packageinfo.inc file and trigger execution by accessing the About tab of the installed extension.

CVSS v3
8.8
EG Score
8.8(medium)
EG Risk
56(Track*)
EG Risk 56/100SSVC: Track*

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
Severity88% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Watch closely — could escalate to Attend.
EPSS PROB
1%
EPSS %ILE
51%
KEV
Not listed

Published

May 15, 2026

Last Modified

May 18, 2026

Advisory Details (3)

Auto-updated May 18, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic

Schlix CMS 2.2.6-6 Remote Code Execution via core.blockmanager | Advisories | VulnCheck

https://www.vulncheck.com/advisories/schlix-cms-6-remote-code-execution-via-core-blockmanager
generic

SCHLIX - Free CMS, blog and website builder (open source) for PHP/MySQL

https://www.schlix.com/
generic🟡 PoC Available

Schlix CMS 2.2.6-6 - Remote Code Execution (Authenticated) - Multiple webapps Exploit

https://www.exploit-db.com/exploits/49838

Vendor Advisories for CVE-2021-47964(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 70× 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 253 total refreshes for this CVE.

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

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Frequently asked(5)

What is CVE-2021-47964?
CVE-2021-47964 is a high vulnerability published on May 15, 2026. Schlix CMS 2.2.6-6 contains a remote code execution vulnerability that allows authenticated attackers to execute arbitrary PHP code by uploading malicious extension packages through the block manager. Attackers can upload a crafted ZIP file containing PHP code in the packageinfo.inc file and…
When was CVE-2021-47964 disclosed?
CVE-2021-47964 was first published in the National Vulnerability Database on May 15, 2026, with the most recent update on May 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-47964 actively exploited?
CVE-2021-47964 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 49.4% of all scored CVEs.
What is the CVSS score of CVE-2021-47964?
CVE-2021-47964 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2021-47964?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-47964, 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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