CVE-2026-84966

MEDIUMPre-NVD 5.15.1—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.1%, top 99% 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
5.1EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.1Exploit: None knownExposed: 0

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

An incorrect numeric type conversion in the BSON document building component of the MongoDB C++ Driver may cause a length value to be interpreted incorrectly. When an application supplies an extremely large, non-terminated field name to the builder, the library may read memory outside the intended buffer and terminate the calling process. No authentication is required, but the calling application must pass the oversized name in a specific form.

CVSS v3
5.1
EG Score
5.1(medium)
EG Risk
23(Track)
EG Risk 23/100SSVC: 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
Severity51% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
1%
KEV
Not listed

Published

September 3, 2026

Last Modified

September 3, 2026

Advisory Details (1)

Auto-updated Sep 3, 2026
No patch confirmed yet.
generic

SAML Login - MongoDB Jira - MongoDB Jira

https://jira.mongodb.org/browse/CXX-3548

Affected Packages

(1 across 1 ecosystem)
Debian:14(1)
PackageVulnerable rangeFixed inDependents
mongo-cxx-driver3.10.1-1 ... 4.5.2-1 (22 versions)——

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 25× 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. 2026-09-18 16:17 UTCEG score recompute
  2. 2026-09-17 19:32 UTCEPSS rescore
  3. 2026-09-17 14:17 UTCEG score recompute
  4. 2026-09-16 14:09 UTCEPSS rescore
  5. 2026-09-15 11:00 UTCEG score recompute
  6. 2026-09-15 03:12 UTCEPSS rescore
  7. 2026-09-15 03:12 UTCEPSS rescore
  8. 2026-09-14 08:55 UTCEG score recompute
  9. 2026-09-13 07:17 UTCEG score recompute
  10. 2026-09-12 05:40 UTCEG score recompute
  11. 2026-09-11 14:53 UTCEPSS rescore
  12. 2026-09-11 14:53 UTCEPSS rescore
  13. 2026-09-11 04:02 UTCEG score recompute
  14. 2026-09-09 00:47 UTCEG score recompute
  15. 2026-09-08 22:01 UTCEPSS rescore
  16. 2026-09-07 23:09 UTCEG score recompute
  17. 2026-09-06 21:31 UTCEG score recompute
  18. 2026-09-06 13:48 UTCEPSS rescore
  19. 2026-09-05 19:53 UTCEG score recompute
  20. 2026-09-05 15:31 UTCEPSS rescore
  21. 2026-09-04 18:16 UTCEG score recompute
  22. 2026-09-03 16:33 UTCEG score recompute
  23. 2026-09-03 15:46 UTCEG score recompute
  24. 2026-09-03 15:24 UTCEG score recompute
  25. 2026-09-03 15:23 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-84966?
CVE-2026-84966 is a medium vulnerability published on September 3, 2026. An incorrect numeric type conversion in the BSON document building component of the MongoDB C++ Driver may cause a length value to be interpreted incorrectly. When an application supplies an extremely large, non-terminated field name to the builder, the library may read memory outside the intended…
When was CVE-2026-84966 disclosed?
CVE-2026-84966 was first published in the National Vulnerability Database on September 3, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-84966 actively exploited?
CVE-2026-84966 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 98.6% of all scored CVEs.
What is the CVSS score of CVE-2026-84966?
CVE-2026-84966 has a CVSS v3 base score of 5.1 (NVD).
How do I remediate CVE-2026-84966?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-84966, 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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