BlackTreeCVE Intelligence
← Back to the CVE catalogue
Full vulnerability report · 2026
CVE-2026-88026High confidence

Regular expression injection via unescaped characters in LINQ query translation in MongoDB C# Driver

MongoDB · C# Driver

7.1HighCVSS 4.0
Recommended action
Within 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Fix not verified
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:High, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • EPSS is 0.38% for the current model date.

Compensating controls

  • Restrict the affected network interface to trusted sources where business-safe.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs MongoDB C# Driver and falls inside the recorded affected range.
  2. Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 30 daysRemediation target: Within 180 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-75640

No EUVD known-exploited evidence

Improper neutralization of regular-expression metacharacters in the LINQ query translation component of the MongoDB C# Driver can cause a caller-supplied character sequence to alter a regular-expression predicate generated by an affected application. An authenticated user who can influence such a value may cause the application to return records beyond those intended by the original filter.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
7.1 · CVSS 4.0
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Fix not verified
01

What, why and how

Improper neutralization of regular-expression metacharacters in the LINQ query translation component of the MongoDB C# Driver can cause a caller-supplied character sequence to alter a regular-expression predicate generated by an affected application. An authenticated user who can influence such a value may cause the application to return records beyond those intended by the original filter.

What

Improper neutralization of regular-expression metacharacters in the LINQ query translation component of the MongoDB C# Driver can cause a caller-supplied character sequence to alter a regular-expression predicate generated by an affected application. An authenticated user who can influence such a value may cause the application to return records beyond those intended by the original filter.

Why

The product generates a query intended to access or manipulate data in a data store such as a database, but it does not neutralize or incorrectly neutralizes special elements that can modify the intended logic of the query.

How

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Improper neutralization of regular-expression metacharacters in the LINQ query translation component of the MongoDB C# Driver can cause a caller-supplied character sequence to alter a regular-expression predicate generated by an affected application. An authenticated user who can influence such a value may cause the application to return records beyond those intended by the original filter.

Why

The product generates a query intended to access or manipulate data in a data store such as a database, but it does not neutralize or incorrectly neutralizes special elements that can modify the intended logic of the query.

How

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Improper Neutralization of Special Elements in Data Query Logic → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
Low: a basic authenticated account is required
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Not a CVSS 4.0 base metric
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-943 ↗

CWE-943: Improper Neutralization of Special Elements in Data Query Logic. The product generates a query intended to access or manipulate data in a data store such as a database, but it does not neutralize or incorrectly neutralizes special elements that can modify the intended logic of the query.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Common Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.ATNoneAttack requirements: No additional deployment or execution condition is required.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.VCHighVulnerable-system confidentiality: A successful attack can cause a major loss.VINoneVulnerable-system integrity: No direct loss is represented by this metric.VANoneVulnerable-system availability: No direct loss is represented by this metric.SCNoneSubsequent-system confidentiality: No direct loss is represented by this metric.SINoneSubsequent-system integrity: No direct loss is represented by this metric.SANoneSubsequent-system availability: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkCWE-943
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-75640Official EUVD mapping

Improper neutralization of regular-expression metacharacters in the LINQ query translation component of the MongoDB C# Driver can cause a caller-supplied character sequence to alter a regular-expression predicate generated by an affected application. An authenticated user who can influence such a value may cause the application to return records beyond those intended by the original filter.

Official EUVD record ↗
BSI · German · WID-SEC-2026-3320MongoDB: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in MongoDB ausnutzen, um Abfrage- und Zugriffsbeschränkungen zu umgehen, nicht vorgesehene Datensätze oder Dateien auszulesen, zu verändern oder zu löschen sowie unter bestimmten Voraussetzungen MongoDB-Server oder Anwendungen zum Absturz zu bringen und dadurch einen Denial-of-Service zu verursachen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260916Security Bulletin 16 Sep 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 16 Sep 2026, published on 16 September 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-1169Multiples vulnérabilités dans MongoDB

De multiples vulnérabilités ont été découvertes dans MongoDB. Certaines d'entre elles permettent à un attaquant de provoquer un déni de service à distance, une atteinte à la confidentialité des données et une atteinte à l'intégrité des données.

Official advisory ↗
CSIRT Italia · Italian · rilevate-vulnerabilita-in-prodotti-mongodb-4Rilevate vulnerabilità in prodotti MongoDB

Aggiornamenti di sicurezza MongoDB sanano molteplici vulnerabilità, di cui 5 con gravità "alta", presenti nel framework PHP Laravel MongoDB Integration e nelle librerie Java Driver e C# Driver di MongoDB. Tali vulnerabilità, qualora sfruttate, potrebbero consentire ad un utente malintenzionato di accedere a contenuti sensibili, di manipolare le informazioni e compromettere la disponibilità del servizio sui sistemi interessati.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-036009MongoDB Inc.のMongoDB C# Driverにおけるデータクエリロジックの特殊要素の不適切な中立化に関する脆弱性

MongoDB C# ドライバーの LINQ クエリ変換コンポーネントにおける正規表現メタ文字の不適切な無害化により、呼び出し元が提供する文字列が影響を受けたアプリケーションによって生成された正規表現述語を変更してしまう可能性があります。認証済みのユーザーがこれらの値に影響を与えられる場合、アプリケーションは元のフィルターが意図した範囲を超えるレコードを返すことがあります。

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Fix not verified
Affected
C# Driver: 2.14.0 ≤ 3.11.1
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 10 Sept 2026 · Last source change 10 Sept 2026, 18:24 UTC · CWE-943 · Improper Neutralization of Special Elements in Data Query Logic

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-09-11
European sourceENISA EUVD · EUVD-2026-75640
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. ENISA EUVD mappingEUVD-2026-75640 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-75640"}
    ENISA EUVD ↗
  2. Vendor guidanceAuthoritative vendor guidance changed: added vendor advisory: jira.mongodb.org/CSHARP-6177.
    Before
    no authoritative guidance recorded
    After
    vendor advisory: jira.mongodb.org/CSHARP-6177
    cna@mongodb.com ↗
  3. Affected versionsThe structured affected or fixed version information changed.
    Before
    2.14.0 ≤ 3.11.1 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    C# Driver: 2.14.0 ≤ 3.11.1 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    CNA ↗
  4. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
ENISA EUVD · EUVD-2026-75640↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-88026 · cve.blacktree.nl