CVE-2021-47934

MEDIUMNVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

Score 5.3 from GitHub Security Advisory published 2026-05-16. NVD baseline CVSS 5.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Elevated
5.3
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.3Exploit: NoneExposed: 0

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

MyBB Timeline Plugin 1.0 contains cross-site scripting vulnerabilities that allow attackers to inject malicious scripts through thread titles, post content, and user profile fields like Location and Bio. Attackers can also exploit a cross-site request forgery vulnerability in the timeline.php profile action to change a user's cover picture by crafting malicious forms that execute when victims visit affected profiles.

CVSS v3
5.3
EG Score
5.3(medium)
EPSS
14.0%
KEV
Not listed

Published

May 16, 2026

Last Modified

May 18, 2026

Advisory Details (3)

Auto-updated May 16, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic

MyBB Timeline Plugin 1.0 Cross-Site Scripting and CSRF | Advisories | VulnCheck

https://www.vulncheck.com/advisories/mybb-timeline-plugin-cross-site-scripting-and-csrf
generic🟡 PoC Available

MyBB Timeline Plugin 1.0 - Persistent Cross-Site Scripting - PHP webapps Exploit

https://www.exploit-db.com/exploits/49467
generic
https://community.mybb.com/mods.php?action=view&pid=1428

Vendor Advisories for CVE-2021-47934(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 10× in last 7d / 59× 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 165 total refreshes for this CVE.

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

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2021-47934?
CVE-2021-47934 is a medium vulnerability published on May 16, 2026. MyBB Timeline Plugin 1.0 contains cross-site scripting vulnerabilities that allow attackers to inject malicious scripts through thread titles, post content, and user profile fields like Location and Bio. Attackers can also exploit a cross-site request forgery vulnerability in the timeline.php…
When was CVE-2021-47934 disclosed?
CVE-2021-47934 was first published in the National Vulnerability Database on May 16, 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-2021-47934 actively exploited?
CVE-2021-47934 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 14.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-47934?
CVE-2021-47934 has a CVSS v3 base score of 5.3 (NVD).
How do I remediate CVE-2021-47934?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-47934, 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.

Dependency Blast Radius

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