CVE-2026-81527

MEDIUMPre-NVD 6.56.5
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

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, GitHub Security Advisory, a secondary CVSS source
Trending — 3 sources updated this week
6.5EG
EchelonGraph verdictMonitorRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 6.5Exploit: None knownExposed services: Not assessed

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

The CVE record's CNA (MongoDB, Inc.) lists MongoDB C# Driver versions 2.14.0 up to but not including 3.11.1 as affected. No release containing a fix is confirmed on record.

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
6.5MEDIUMmedium confidence
EG Risk
44
EG Risk 44/100

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 (value × EchelonGraph’s weight)
Severity65% × 45%
The EG Score, 6.5 of 10.
Exploitation0.3% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.
EPSS PROB
0.3%
EPSS %ILE
21st
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

August 27, 2026

Last Modified

September 29, 2026

Advisory Details (1)

Auto-updated Aug 27, 2026
No fix on record yet.
Web page

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 15× in last 7d / 76× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 98 of 129 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 2 repeat rows among the latest 100 are merged into the row they repeat. The 31 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  2. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  3. 2026-10-12 14:56 UTCEG score recompute
  4. 2026-10-11 19:20 UTCEG score recompute
  5. 2026-10-11 16:37 UTCEG score recompute
  6. 2026-10-11 13:55 UTCEG score recompute
  7. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  8. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  9. 2026-10-10 05:19 UTCEG score recompute
  10. 2026-10-10 05:19 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  11. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  12. 2026-10-09 02:57 UTCEG score recompute
  13. 2026-10-09 02:57 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  14. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  15. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  16. 2026-10-07 10:42 UTCEG score recompute
  17. 2026-10-07 10:42 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  18. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  19. 2026-10-06 08:48 UTCEG score recompute
  20. 2026-10-06 08:48 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  21. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  22. 2026-10-05 06:52 UTCEG score recompute
  23. 2026-10-05 06:52 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  24. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  25. 2026-10-04 05:00 UTCEG score recompute
Show 73 more
  1. 2026-10-04 05:00 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  2. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  3. 2026-10-03 03:06 UTCEG score recompute
  4. 2026-10-03 03:06 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  5. 2026-10-02 17:57 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  6. 2026-10-02 01:14 UTCEG score recompute
  7. 2026-10-02 01:14 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  8. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  9. 2026-09-30 21:18 UTCEG score recompute
  10. 2026-09-30 21:18 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  11. 2026-09-30 15:04 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  12. 2026-09-29 19:24 UTCEG score recompute
  13. 2026-09-29 19:24 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  14. 2026-09-28 22:21 UTCEG score recompute
  15. 2026-09-28 22:21 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  16. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  17. 2026-09-27 20:16 UTCEG score recompute
  18. 2026-09-27 20:16 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  19. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  20. 2026-09-26 18:24 UTCEG score recompute
  21. 2026-09-26 18:24 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  22. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  23. 2026-09-25 05:04 UTCEG score recompute
  24. 2026-09-25 05:04 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  25. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  26. 2026-09-24 03:12 UTCEG score recompute
  27. 2026-09-24 03:12 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  28. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  29. 2026-09-23 01:20 UTCEG score recompute
  30. 2026-09-23 01:20 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  31. 2026-09-22 16:01 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  32. 2026-09-21 23:28 UTCEG score recompute
  33. 2026-09-21 23:28 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  34. 2026-09-21 21:09 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  35. 2026-09-20 21:35 UTCEG score recompute
  36. 2026-09-20 21:35 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  37. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  38. 2026-09-19 19:43 UTCEG score recompute
  39. 2026-09-19 19:43 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  40. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  41. 2026-09-18 17:51 UTCEG score recompute
  42. 2026-09-18 17:51 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  43. 2026-09-17 15:59 UTCEG score recompute
  44. 2026-09-17 15:59 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  45. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  46. 2026-09-16 14:07 UTCEG score recompute
  47. 2026-09-16 14:07 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  48. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  49. 2026-09-15 11:57 UTCEG score recompute
  50. 2026-09-15 11:57 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  51. 2026-09-15 03:12 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  52. 2026-09-14 10:04 UTCEG score recompute
  53. 2026-09-14 10:04 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  54. 2026-09-13 08:06 UTCEG score recompute
  55. 2026-09-13 08:06 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  56. 2026-09-12 06:14 UTCEG score recompute
  57. 2026-09-12 06:14 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  58. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  59. 2026-09-11 04:22 UTCEG score recompute
  60. 2026-09-11 04:22 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  61. 2026-09-10 02:30 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  62. 2026-09-09 00:38 UTCEG score recompute
  63. 2026-09-09 00:38 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  64. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  65. 2026-09-07 15:05 UTCEG score recompute
  66. 2026-09-07 15:05 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  67. 2026-09-06 13:48 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  68. 2026-09-06 12:29 UTCEG score recompute
  69. 2026-09-06 12:29 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  70. 2026-09-05 15:31 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  71. 2026-09-05 10:37 UTCEG score recompute
  72. 2026-09-05 10:37 UTCGHSA enrichmentGHSA-qvhj-5652-cjrg · GitHub CVSS 6.5
  73. 2026-09-04 08:44 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-81527?
CVE-2026-81527 is a medium-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-81527 published?
The CVE record for CVE-2026-81527 was published on August 27, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 29, 2026; the record at its source may have been updated since.
Is CVE-2026-81527 actively exploited?
CVE-2026-81527 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (21st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-81527?
CVE-2026-81527 has a CVSS base score of 6.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-81527?
No fix for CVE-2026-81527 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The CVE record's CNA (MongoDB, Inc.) lists MongoDB C# Driver versions 2.14.0 up to but not including 3.11.1 as affected. No release containing a fix is confirmed on record. The vendor advisories EchelonGraph has for CVE-2026-81527 are linked in the Vendor Advisories panel on this page.

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