How severe is CVE-2026-9740?

CVE-2026-9740 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-9740 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-9740?

CVE-2026-9740 affects Mongodb. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-9740?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-9740 have an EU (EUVD) identifier?

Yes. CVE-2026-9740 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-35857.

When was CVE-2026-9740 published?

CVE-2026-9740 was published on 2026-06-09 and last updated on 2026-06-17.

CVE-2026-9740

CVE-2026-9740 is a high-severity vulnerability in Mongodb with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-674.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 8.7
EPSS exploit prediction: 0% (26th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-35857
Weakness: CWE-674
Affected product: Mongodb
Published: 2026-06-09
Last modified: 2026-06-17

Description

A vulnerability in MongoDB Server's BSON validation logic allows an unauthenticated user to crash the mongod process by sending a specially crafted message. The BSON validator's handling of certain nested binary data structures permits uncontrolled mutual recursion between validation functions, where each re-entry resets internal depth tracking.

Frequently asked questions

What is CVE-2026-9740?: A vulnerability in MongoDB Server's BSON validation logic allows an unauthenticated user to crash the mongod process by sending a specially crafted message. The BSON validator's handling of certain nested binary data structures permits uncontrolled mutual recursion between validation functions, where each re-entry resets internal depth tracking.
How severe is CVE-2026-9740?: CVE-2026-9740 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-9740 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-9740?: CVE-2026-9740 affects Mongodb. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-9740?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-9740 have an EU (EUVD) identifier?: Yes. CVE-2026-9740 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-35857.
When was CVE-2026-9740 published?: CVE-2026-9740 was published on 2026-06-09 and last updated on 2026-06-17.

References

https://jira.mongodb.org/browse/SERVER-125063

Affected products (1)

cpe:2.3:a:mongodb:mongodb:*:*:*:*:*:*:*:*

More vulnerabilities in Mongodb

CVE-2017-15535 — Critical (CVSS 9.1): MongoDB 3.4.x before 3.4.10, and 3.5.x-development, has a disabled-by-default configuration setting,…
CVE-2026-11933 — High (CVSS 8.8): A use-after-free vulnerability exists in MongoDB Server's server-side JavaScript engine when converting BSON documents…
CVE-2026-8053 — High (CVSS 8.8): An issue in MongoDB Server's time-series collection implementation allows an authenticated user with database write…
CVE-2026-4148 — High (CVSS 8.8): A use-after-free vulnerability can be triggered in sharded clusters by an authenticated user with the read role who…
CVE-2024-1351 — High (CVSS 8.8): Under certain configurations of --tlsCAFile and tls.CAFile, MongoDB Server may skip peer certificate validation which…
CVE-2025-0755 — High (CVSS 8.4): The various bson_append functions in the MongoDB C driver library may be susceptible to buffer overflow when…

All CVEs affecting Mongodb →

Other CWE-674 (Uncontrolled Recursion) vulnerabilities

CVE-2026-43185 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix signededness bug in…
CVE-2023-51803 — Critical (CVSS 9.8): LinuxServer.io Heimdall before 2.5.7 does not prevent use of icons that have non-image data such as the "<?php ?>"…
CVE-2021-41752 — Critical (CVSS 9.8): Stack overflow vulnerability in Jerryscript before commit e1ce7dd7271288be8c0c8136eea9107df73a8ce2 on Oct 20, 2021 due…
CVE-2018-1000618 — Critical (CVSS 9.8): EOSIO/eos eos version after commit f1545dd0ae2b77580c2236fdb70ae7138d2c7168 contains a stack overflow vulnerability in…
CVE-2025-10728 — Critical (CVSS 9.4): When the module renders a Svg file that contains a <pattern> element, it might end up rendering it recursively leading…
CVE-2026-40324 — Critical (CVSS 9.1): Hot Chocolate is an open-source GraphQL server. Prior to versions 12.22.7, 13.9.16, 14.3.1, and 15.1.14, Hot…

Browse all CWE-674 (Uncontrolled Recursion) vulnerabilities →