CVE-2026-46482

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4% (36th percentile of EPSS-scored CVEs). 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, secondary
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 5.3Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Impact

The registration component does not validate the text-based _Security Question_ CAPTCHA correctly, allowing attackers to bypass the challenge via a specially crafted value.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Details

The public _Registration_ workflow (member.php?action=do_register) accepts a hidden field question_id — expected to match the question session identifier (mybb_questionsessions.sid) — and validates the challenge answer without a fail-closed fallback for invalid identifiers. If the value is blank, forged, or expired, the request continues without a question-related error.

Patches

MyBB 1.8.(...) resolves this issue with the following changes:
  • Commit: https://github.com/mybb/mybb/commit/
  • .patch: https://github.com/mybb/mybb/commit/.patch

References

  • Release Notes: https://mybb.com/versions/1.8.(...)/

For more information

Go to mybb.com/security to report possible security concerns or to learn more about security research at MyBB.

Contact

The security team can be reached at [email protected].

CVSS v3
5.3
EG Score
5.3MEDIUMmedium confidence
EG Risk
39
EG Risk 39/100CISA SSVC

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
Severity53% × 45%
Exploitation0% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.4%
EPSS %ILE
36th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 18, 2026

Last Modified

September 8, 2026

Advisory Details (4)

Auto-updated Aug 18, 2026
Patch available. Sources: github, github_commit, github_release.
generic

Version 1.8.40 - MyBB

https://mybb.com/versions/1.8.40
github_release Patch Available

mybb_1840

Patch available: mybb/mybb mybb_1840

https://github.com/mybb/mybb/releases/tag/mybb_1840
github_commit Patch Available

commit bd2a3447939d (mybb/mybb)

Patch available: mybb/mybb mybb_1840 (contains commit bd2a3447939d)

https://github.com/mybb/mybb/commit/bd2a3447939d3084a5926dd66ece04649e0e0d60
githubMentions a patch (unverified)

Security Question insufficient validation · Advisory · mybb/mybb · GitHub

https://github.com/mybb/mybb/security/advisories/GHSA-v2h7-4jp7-j6hh

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 48× 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. 2026-10-09 20:07 UTCEPSS rescore
  2. 2026-10-08 17:12 UTCEPSS rescore
  3. 2026-10-07 23:48 UTCEPSS rescore
  4. 2026-10-07 08:49 UTCEG score recompute
  5. 2026-10-06 15:18 UTCEPSS rescore
  6. 2026-10-06 08:23 UTCEG score recompute
  7. 2026-10-05 17:43 UTCEPSS rescore
  8. 2026-10-04 23:22 UTCEPSS rescore
  9. 2026-10-03 17:39 UTCEG score recompute
  10. 2026-10-03 14:25 UTCEPSS rescore
  11. 2026-10-02 10:25 UTCEG score recompute
  12. 2026-10-01 19:50 UTCEPSS rescore
  13. 2026-10-01 10:07 UTCEG score recompute
  14. 2026-09-30 15:03 UTCEPSS rescore
  15. 2026-09-30 09:49 UTCEG score recompute
  16. 2026-09-29 08:34 UTCEG score recompute
  17. 2026-09-28 13:51 UTCEPSS rescore
  18. 2026-09-28 08:14 UTCEG score recompute
  19. 2026-09-27 13:48 UTCEPSS rescore
  20. 2026-09-27 07:57 UTCEG score recompute
  21. 2026-09-26 15:59 UTCEPSS rescore
  22. 2026-09-26 00:27 UTCEPSS rescore
  23. 2026-09-25 07:19 UTCEG score recompute
  24. 2026-09-24 06:58 UTCEG score recompute
  25. 2026-09-23 17:53 UTCEPSS rescore
Show 63 more
  1. 2026-09-23 06:41 UTCEG score recompute
  2. 2026-09-22 06:23 UTCEG score recompute
  3. 2026-09-21 06:04 UTCEG score recompute
  4. 2026-09-20 20:15 UTCEPSS rescore
  5. 2026-09-20 04:38 UTCEG score recompute
  6. 2026-09-19 04:19 UTCEG score recompute
  7. 2026-09-18 19:28 UTCEPSS rescore
  8. 2026-09-18 04:01 UTCEG score recompute
  9. 2026-09-17 19:31 UTCEPSS rescore
  10. 2026-09-17 03:43 UTCEG score recompute
  11. 2026-09-16 14:08 UTCEPSS rescore
  12. 2026-09-16 05:15 UTCEPSS rescore
  13. 2026-09-16 02:57 UTCEG score recompute
  14. 2026-09-14 02:21 UTCEG score recompute
  15. 2026-09-13 16:47 UTCEPSS rescore
  16. 2026-09-13 02:03 UTCEG score recompute
  17. 2026-09-12 15:01 UTCEPSS rescore
  18. 2026-09-12 01:44 UTCEG score recompute
  19. 2026-09-11 14:53 UTCEPSS rescore
  20. 2026-09-11 09:37 UTCEPSS rescore
  21. 2026-09-11 01:26 UTCEG score recompute
  22. 2026-09-10 09:34 UTCEPSS rescore
  23. 2026-09-10 01:08 UTCEG score recompute
  24. 2026-09-08 22:00 UTCEPSS rescore
  25. 2026-09-08 21:17 UTCEG score recompute
  26. 2026-09-07 16:01 UTCEPSS rescore
  27. 2026-09-07 10:26 UTCEG score recompute
  28. 2026-09-06 13:47 UTCEPSS rescore
  29. 2026-09-06 07:09 UTCEG score recompute
  30. 2026-09-05 06:47 UTCEG score recompute
  31. 2026-09-04 06:09 UTCEG score recompute
  32. 2026-09-04 05:06 UTCEPSS rescore
  33. 2026-09-03 05:49 UTCEG score recompute
  34. 2026-09-02 14:12 UTCEPSS rescore
  35. 2026-09-02 05:24 UTCEG score recompute
  36. 2026-09-01 13:54 UTCEPSS rescore
  37. 2026-09-01 04:59 UTCEG score recompute
  38. 2026-08-31 04:34 UTCEG score recompute
  39. 2026-08-30 19:17 UTCEPSS rescore
  40. 2026-08-30 04:16 UTCEG score recompute
  41. 2026-08-30 01:22 UTCEPSS rescore
  42. 2026-08-29 03:58 UTCEG score recompute
  43. 2026-08-28 21:41 UTCEPSS rescore
  44. 2026-08-27 21:14 UTCEG score recompute
  45. 2026-08-27 14:25 UTCEPSS rescore
  46. 2026-08-26 20:57 UTCEG score recompute
  47. 2026-08-26 14:46 UTCEPSS rescore
  48. 2026-08-25 20:38 UTCEG score recompute
  49. 2026-08-25 13:49 UTCEPSS rescore
  50. 2026-08-24 20:13 UTCEG score recompute
  51. 2026-08-23 19:55 UTCEG score recompute
  52. 2026-08-23 00:19 UTCEPSS rescore
  53. 2026-08-22 19:37 UTCEG score recompute
  54. 2026-08-21 23:49 UTCEPSS rescore
  55. 2026-08-21 19:19 UTCEG score recompute
  56. 2026-08-20 22:55 UTCEPSS rescore
  57. 2026-08-19 18:43 UTCEG score recompute
  58. 2026-08-19 17:04 UTCEPSS rescore
  59. 2026-08-18 18:24 UTCEG score recompute
  60. 2026-08-18 18:00 UTCEG score recompute
  61. 2026-08-18 16:30 UTCEG score recompute
  62. 2026-08-18 15:59 UTCEG score recompute
  63. 2026-08-18 15:59 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-46482?
CVE-2026-46482 is a medium vulnerability published on August 18, 2026. Impact The registration component does not validate the text-based Security Question CAPTCHA correctly, allowing attackers to bypass the challenge via a specially crafted value. CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N Details The public Registration workflow (member.php?action=doregister)…
When was CVE-2026-46482 disclosed?
CVE-2026-46482 was first published on August 18, 2026, with the most recent update on September 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-46482 actively exploited?
CVE-2026-46482 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (36th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-46482?
CVE-2026-46482 has a CVSS base score of 5.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-46482?
A fix for CVE-2026-46482 is available: update to the fixed version the vendor names in its advisory.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-46482

Explore →

Is Your Infrastructure Affected by CVE-2026-46482?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Book a Demo →Browse All CVEs