8.7

CVE-2026-9740: mongodb Uncontrolled Recursion

CVSS: 8.7v4.0HighAnalyzed
AliasesUBUNTU-CVE-2026-9740
Published 09-06-2026Last modified 10-06-2026
Open JSON

Vulnerability summary

CVE-2026-9740 is a high (CVSS 8.7) Uncontrolled Recursion vulnerability in mongodb. EPSS estimates a 0.53% chance of exploitation in the next 30 days, higher than 43.5% of scored vulnerabilities.

Overall risk
35/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.7/10
010
High · v4.0 (CVE.org)
EPSS score
0.53%
0%100%
Low · +0.18 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 09-06-2026
    PublishedVulnerability first disclosed.
  2. 10-06-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

6 scores · 3 sources · 2 versions

EPSS trend

Probability

0.53%

Chance of exploitation in the next 30 days

Percentile

44%

Versus all other CVEs

30-day change

+0.18 pp

From 0.34% on 18-09-2026

18-09-202618-10-2026
EPSS score
0.53%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Mongodb2 products
  • mongodb≥ 7.0.0, < 7.0.35 | ≥ 8.0.0, < 8.0.24 | ≥ 8.2.0, < 8.2.10 | ≥ 8.3.0, < 8.3.3
  • mongodb server≥ 8.3.0, < 8.3.3 | ≥ 8.2.0, < 8.2.10 | ≥ 8.0.0, < 8.0.24 | ≥ 7.0.0, < 7.0.35
Ubuntu1 product
  • mongodbAll versions (No fix recorded)

2 vendors · 3 products

References

3 links