CVE-2026-8337

MEDIUMNVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

Score 5.3 from GitHub Security Advisory published 2026-05-22. NVD baseline CVSS 5.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
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.

Concrete CMS 9.5.0 and below is vulnerable to IDOR in surveys. To be vulnerable, a site would have to be configured in such a way that both public and private surveys are present on the site. An unauthenticated attacker can vote in the restricted survey by submitting the restricted optionID through the public survey’s endpoint. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 6.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks  Zer0daySec https://github.com/Zee99y  for reporting

CVSS v3
5.3
EG Score
5.3(medium)
EPSS
9.3%
KEV
Not listed

Published

May 21, 2026

Last Modified

May 26, 2026

Advisory Details (1)

Auto-updated Jun 16, 2026
No patch confirmed yet.
generic

9.5.1 Release Notes :: Concrete CMS

https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes

Vendor Advisories for CVE-2026-8337(1)

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

Affected Packages

(1 across 1 ecosystem)
Packagist(1)
PackageVulnerable rangeFixed inDependents
concrete5/concrete58.0 ... 9.5.0RC2 (89 versions)9.5.1—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 12× in last 7d / 53× 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. 2026-07-11 08:27 UTCEPSS rescore
  2. 2026-07-09 19:10 UTCEPSS rescore
  3. 2026-07-08 15:16 UTCEPSS rescore
  4. 2026-07-08 15:16 UTCEPSS rescore
  5. 2026-07-07 13:46 UTCEPSS rescore
  6. 2026-07-07 13:46 UTCEPSS rescore
  7. 2026-07-06 16:27 UTCEPSS rescore
  8. 2026-07-06 16:27 UTCEPSS rescore
  9. 2026-07-06 02:23 UTCEPSS rescore
  10. 2026-07-06 02:23 UTCEPSS rescore
  11. 2026-07-05 02:31 UTCEPSS rescore
  12. 2026-07-05 02:30 UTCEPSS rescore
  13. 2026-07-04 06:31 UTCEPSS rescore
  14. 2026-07-04 06:31 UTCEPSS rescore
  15. 2026-07-01 15:07 UTCEPSS rescore
  16. 2026-06-30 23:22 UTCEPSS rescore
  17. 2026-06-29 16:43 UTCEG score recompute
  18. 2026-06-29 14:06 UTCEPSS rescore
  19. 2026-06-28 14:07 UTCEPSS rescore
  20. 2026-06-28 04:56 UTCEPSS rescore
  21. 2026-06-27 19:32 UTCEG score recompute
  22. 2026-06-27 03:08 UTCEPSS rescore
  23. 2026-06-26 19:16 UTCEG score recompute
  24. 2026-06-25 14:12 UTCEG score recompute
  25. 2026-06-25 13:50 UTCEPSS rescore
Show 74 more
  1. 2026-06-24 14:05 UTCEPSS rescore
  2. 2026-06-23 21:33 UTCEPSS rescore
  3. 2026-06-22 14:25 UTCEPSS rescore
  4. 2026-06-21 14:56 UTCEPSS rescore
  5. 2026-06-21 01:59 UTCEPSS rescore
  6. 2026-06-19 19:26 UTCEPSS rescore
  7. 2026-06-18 17:52 UTCEPSS rescore
  8. 2026-06-17 19:56 UTCEG score recompute
  9. 2026-06-17 19:56 UTCGHSA enrichment
  10. 2026-06-16 21:03 UTCEG score recompute
  11. 2026-06-16 21:03 UTCGHSA enrichment
  12. 2026-06-16 17:53 UTCEPSS rescore
  13. 2026-06-15 22:46 UTCEG score recompute
  14. 2026-06-15 22:46 UTCGHSA enrichment
  15. 2026-06-15 17:49 UTCEPSS rescore
  16. 2026-06-15 17:49 UTCEPSS rescore
  17. 2026-06-14 23:57 UTCEG score recompute
  18. 2026-06-14 23:57 UTCGHSA enrichment
  19. 2026-06-14 23:18 UTCEPSS rescore
  20. 2026-06-14 01:45 UTCEG score recompute
  21. 2026-06-14 01:45 UTCGHSA enrichment
  22. 2026-06-13 23:00 UTCEPSS rescore
  23. 2026-06-13 03:24 UTCEG score recompute
  24. 2026-06-13 03:24 UTCGHSA enrichment
  25. 2026-06-12 23:12 UTCEPSS rescore
  26. 2026-06-12 23:12 UTCEPSS rescore
  27. 2026-06-12 05:07 UTCEG score recompute
  28. 2026-06-12 05:07 UTCGHSA enrichment
  29. 2026-06-11 14:00 UTCEPSS rescore
  30. 2026-06-11 06:55 UTCEG score recompute
  31. 2026-06-11 06:55 UTCGHSA enrichment
  32. 2026-06-10 22:19 UTCEPSS rescore
  33. 2026-06-10 13:22 UTCEPSS rescore
  34. 2026-06-10 08:44 UTCEG score recompute
  35. 2026-06-10 08:44 UTCGHSA enrichment
  36. 2026-06-09 10:32 UTCEG score recompute
  37. 2026-06-09 10:32 UTCGHSA enrichment
  38. 2026-06-08 14:17 UTCEPSS rescore
  39. 2026-06-08 12:20 UTCEG score recompute
  40. 2026-06-08 12:20 UTCGHSA enrichment
  41. 2026-06-07 15:25 UTCEPSS rescore
  42. 2026-06-07 14:08 UTCEG score recompute
  43. 2026-06-07 14:08 UTCGHSA enrichment
  44. 2026-06-06 15:48 UTCEG score recompute
  45. 2026-06-06 15:48 UTCGHSA enrichment
  46. 2026-06-06 13:47 UTCEPSS rescore
  47. 2026-06-05 22:47 UTCEPSS rescore
  48. 2026-06-05 17:36 UTCEG score recompute
  49. 2026-06-05 17:36 UTCGHSA enrichment
  50. 2026-06-05 06:10 UTCEPSS rescore
  51. 2026-06-04 19:23 UTCEG score recompute
  52. 2026-06-04 19:23 UTCGHSA enrichment
  53. 2026-06-04 13:12 UTCEPSS rescore
  54. 2026-06-03 21:11 UTCEG score recompute
  55. 2026-06-03 21:11 UTCGHSA enrichment
  56. 2026-06-02 22:59 UTCEG score recompute
  57. 2026-06-02 22:59 UTCGHSA enrichment
  58. 2026-06-02 20:13 UTCEPSS rescore
  59. 2026-06-02 00:47 UTCEG score recompute
  60. 2026-06-02 00:47 UTCGHSA enrichment
  61. 2026-06-01 13:52 UTCEPSS rescore
  62. 2026-06-01 02:35 UTCEG score recompute▼ 1.00
  63. 2026-06-01 02:35 UTCGHSA enrichment
  64. 2026-05-31 22:30 UTCEPSS rescore
  65. 2026-05-31 00:16 UTCEPSS rescore
  66. 2026-05-29 13:44 UTCEPSS rescore
  67. 2026-05-28 13:44 UTCEPSS rescore
  68. 2026-05-27 13:40 UTCEPSS rescore
  69. 2026-05-27 13:40 UTCEPSS rescore
  70. 2026-05-26 13:44 UTCEPSS rescore
  71. 2026-05-26 07:18 UTCEPSS rescore
  72. 2026-05-23 00:07 UTCEG score recompute
  73. 2026-05-22 22:08 UTCEG score recompute
  74. 2026-05-21 22:44 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-8337?
CVE-2026-8337 is a medium vulnerability published on May 21, 2026. Concrete CMS 9.5.0 and below is vulnerable to IDOR in surveys. To be vulnerable, a site would have to be configured in such a way that both public and private surveys are present on the site. An unauthenticated attacker can vote in the restricted survey by submitting the restricted optionID through…
When was CVE-2026-8337 disclosed?
CVE-2026-8337 was first published in the National Vulnerability Database on May 21, 2026, with the most recent update on May 26, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-8337 actively exploited?
CVE-2026-8337 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 9.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-8337?
CVE-2026-8337 has a CVSS v3 base score of 5.3 (NVD).
How do I remediate CVE-2026-8337?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-8337, 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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