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VulnerabilityPublished

CVE-2026-9740: MongoDB Server · Uncontrolled Recursion

Affects MongoDB ServerSource CVE Database V5

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Not known to be exploited · CVSS 8.7 High · fixed in 8.3.3 : patch MongoDB Server soon.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 4.0 base score
8.7High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 27% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 8.3.3, 8.2.10, 8.0.24 +1
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 9 Jun 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

Upgrade MongoDB Server to 8.3.3, 8.2.10, 8.0.24 or 7.0.35.

Affected software

ProductAffectedFixed in
MongoDBMongoDB ServerAffected
  • >=8.3.0 <8.3.3
Fixed in
  • 8.3.3
MongoDBMongoDB ServerAffected
  • >=8.2.0 <8.2.10
Fixed in
  • 8.2.10
MongoDBMongoDB ServerAffected
  • >=8.0.0 <8.0.24
Fixed in
  • 8.0.24
MongoDBMongoDB ServerAffected
  • >=7.0.0 <7.0.35
Fixed in
  • 7.0.35

AI-suggested

If you cannot patch yet, consider restricting network access to MongoDB instances to trusted sources to reduce exposure to unauthenticated attacks.

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.

References

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