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CVE-2026-120809VulnerabilityPublished

MongoDB’s SBE (Slot-Based Execution) engine · Use-after-free Read Issue Exists

Source GCVE Database

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Authoritative record:CVE-2026-120809· Medium 6.1

Not known to be exploited · CVSS 6.1 Medium · fixed in 9.0.7 : update MongoDB Server when convenient.

Data as of 10 Nov 2026, 22:34 UTC

CVSS 4.0 base score
6.1Medium
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (mongodb)CVSS 4.06.1
CNA (mongodb)CVSS 3.16.8
Patch
Available – fixed in 9.0.7, 8.3.16, 8.0.37
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 10 Nov 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 10 Nov 2026.

What to do

Upgrade MongoDB Server to 9.0.7, 8.3.16 or 8.0.37.

Affected software

ProductAffectedFixed in
MongoDBMongoDB ServerAffected
  • >=9.0.0 <9.0.7
Fixed in
  • 9.0.7
MongoDBMongoDB ServerAffected
  • >=8.3.0 <8.3.16
Fixed in
  • 8.3.16
MongoDBMongoDB ServerAffected
  • >=8.0.0 <8.0.37
Fixed in
  • 8.0.37

Description

A use-after-free read issue exists in MongoDB’s SBE (Slot-Based Execution) engine when processing aggregation pipelines with $unwind on time-series collections. An internal error in state-preservation logic can cause a value still referenced by downstream stages to have its underlying memory freed prematurely. An authenticated user can craft an aggregation pipeline under specific conditions to trigger this condition, potentially reading recycled server heap memory in query results or crashing the server. This issue is only triggerable when a non-default server parameter related to the SBE engine is enabled.

References

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