CVE-2026-81527

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreHIGH confidence

Score 6.5 from GitHub Security Advisory published 2026-08-27. a secondary CVSS source baseline 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.5Exploit: None knownExposed: 0

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

A NoSQL/expression injection weakness exists in the LINQ-to-aggregation query translation layer of the MongoDB C# Driver, in both aggregation expression and query filter translation. When application-supplied values are embedded in certain query constructs, special elements contained within those values are not properly escaped before the resulting query is transmitted to the database, so portions of the value may be interpreted by the database as query logic rather than as data. A user able to supply values that an application incorporates into an affected query may thereby cause unintended data to be returned or query results to be altered.

CVSS v3
6.5
EG Score
6.5(high)
EG Risk
44(Track)
EG Risk 44/100SSVC: 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
Severity65% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
8%
KEV
Not listed

Published

August 27, 2026

Last Modified

August 28, 2026

Advisory Details (1)

Auto-updated Aug 27, 2026
No patch confirmed yet.
generic

NuGet Gallery | MongoDB.Driver 3.11.1

https://www.nuget.org/packages/MongoDB.Driver/3.11.1

Vendor Advisories for CVE-2026-81527(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 16× in last 7d / 16× 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 23:15 UTCEG score recompute
  3. 2026-08-29 23:15 UTCGHSA enrichment
  4. 2026-08-28 21:42 UTCEPSS rescore
  5. 2026-08-28 21:22 UTCGHSA enrichment
  6. 2026-08-28 20:41 UTCEG score recompute
  7. 2026-08-28 20:41 UTCGHSA enrichment
  8. 2026-08-28 19:46 UTCEG score recompute
  9. 2026-08-28 19:46 UTCGHSA enrichment
  10. 2026-08-28 00:32 UTCEG score recompute
  11. 2026-08-28 00:32 UTCGHSA enrichment
  12. 2026-08-27 23:24 UTCEG score recompute
  13. 2026-08-27 23:24 UTCGHSA enrichment
  14. 2026-08-27 20:26 UTCEG score recompute
  15. 2026-08-27 20:15 UTCEG score recompute
  16. 2026-08-27 20:13 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-81527?
CVE-2026-81527 is a medium vulnerability published on August 27, 2026. A NoSQL/expression injection weakness exists in the LINQ-to-aggregation query translation layer of the MongoDB C# Driver, in both aggregation expression and query filter translation. When application-supplied values are embedded in certain query constructs, special elements contained within those…
When was CVE-2026-81527 disclosed?
CVE-2026-81527 was first published in the National Vulnerability Database on August 27, 2026, with the most recent update on August 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-81527 actively exploited?
CVE-2026-81527 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 92.1% of all scored CVEs.
What is the CVSS score of CVE-2026-81527?
CVE-2026-81527 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-81527?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-81527, 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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