CVE-2026-45119

MEDIUMPre-NVD 4.64.6—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 4.6 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.1%, top 97% of all CVEs by exploit prediction. 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
4.6EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 4.6Exploit: None knownExposed: 0

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

MyBB is free and open source forum software. Prior to 1.8.40, the Admin CP UTF-8 Conversion module does not validate certain requests correctly, allowing same-site attackers to alter table encoding and deny service with a specially crafted URL. The do=all control flow in admin/modules/tools/system_health.php performs ALTER TABLE operations, column rewrite phases, and fulltext index rebuilds on GET requests for the database table named by the table parameter without request verification. The uniquely identifying implementation details include GET requests without request verification. This issue is fixed in version 1.8.40.

CVSS v3
4.6
EG Score
4.6(medium)
EG Risk
21(Track)
EG Risk 21/100SSVC: 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
Severity46% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
3%
KEV
Not listed

Published

August 18, 2026

Last Modified

August 19, 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 70d445d14c83 (mybb/mybb)

Patch available: mybb/mybb mybb_1840 (contains commit 70d445d14c83)

https://github.com/mybb/mybb/commit/70d445d14c8350cc014be66f7874611abef70ab4
github Patch Available

ACP UTF-8 Conversion CSRF · Advisory · mybb/mybb · GitHub

https://github.com/mybb/mybb/security/advisories/GHSA-p48q-4vgf-q7x8

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 21× 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. 2026-08-30 01:22 UTCEPSS rescore
  2. 2026-08-29 10:12 UTCEG score recompute
  3. 2026-08-28 21:41 UTCEPSS rescore
  4. 2026-08-28 08:09 UTCEG score recompute
  5. 2026-08-27 14:25 UTCEPSS rescore
  6. 2026-08-26 03:42 UTCEG score recompute
  7. 2026-08-25 13:49 UTCEPSS rescore
  8. 2026-08-25 01:39 UTCEG score recompute
  9. 2026-08-23 23:36 UTCEG score recompute
  10. 2026-08-23 00:19 UTCEPSS rescore
  11. 2026-08-22 21:34 UTCEG score recompute
  12. 2026-08-21 23:49 UTCEPSS rescore
  13. 2026-08-21 19:31 UTCEG score recompute
  14. 2026-08-20 22:55 UTCEPSS rescore
  15. 2026-08-20 17:28 UTCEG score recompute
  16. 2026-08-19 17:04 UTCEPSS rescore
  17. 2026-08-19 15:25 UTCEG score recompute
  18. 2026-08-19 14:58 UTCEG score recompute
  19. 2026-08-18 16:30 UTCEG score recompute
  20. 2026-08-18 15:59 UTCEG score recompute
  21. 2026-08-18 15:59 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-45119?
CVE-2026-45119 is a medium vulnerability published on August 18, 2026. MyBB is free and open source forum software. Prior to 1.8.40, the Admin CP UTF-8 Conversion module does not validate certain requests correctly, allowing same-site attackers to alter table encoding and deny service with a specially crafted URL. The do=all control flow in…
When was CVE-2026-45119 disclosed?
CVE-2026-45119 was first published in the National Vulnerability Database on August 18, 2026, with the most recent update on August 19, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-45119 actively exploited?
CVE-2026-45119 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 97.2% of all scored CVEs.
What is the CVSS score of CVE-2026-45119?
CVE-2026-45119 has a CVSS v3 base score of 4.6 (NVD).
How do I remediate CVE-2026-45119?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-45119, 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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