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CVE.org (no NVD analysis yet)· CNA mongodb

CVE-2026-120818: Use-After-Free in MongoDB Server JavaScript Support for Aggregation Leads to Information Disclosure

HighCVSS 7.1 · v4.0—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 28/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.39% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: MongoDB MongoDB Server 7.0.48, 8.0.37, 8.3.16.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to MongoDB MongoDB Server 7.0.48, 8.0.37, 8.3.16 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

A use-after-free weakness in MongoDB Server's server-side JavaScript support for aggregation may allow a stale reference to previously freed process memory to be read and returned. An authenticated user with minimal or no assigned roles can trigger this condition over the normal network protocol by submitting a single crafted aggregation request, with no additional privileges or non-default configuration. Successful triggering this issue may result in adjacent process memory contents being returned, including data that undermines memory-layout randomization, and may in some cases affect server availability.

Published
Nov 10, 2026
Updated
Nov 10, 2026
EPSS
0.3% · 34th percentile

Report tools

JSON

Action score

28

Monitor

Low priority for now.

CVSS
28 / 40 · 7.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CNA vs NVD score

NVD
—
CNA · mongodb
7.1
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:L/SC:N/SI:N/SA:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-120818

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (mongodb). Independent of NVD's CPE analysis and usually ahead of it.

  • MongoDB MongoDB Server

    • 8.3.0 and later · before 8.3.16affected · semver
    • 8.0.0 and later · before 8.0.37affected · semver
    • 7.0.0 and later · before 7.0.48affected · semver

Same product

mongodb: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-118383Pre-authentication use-after-free in MongoDB Server replica set primary catch-up
    38Monitor
  • CVE-2026-120808Certificate Validation Bypass via IPv6 trust-result skip in macOS TLS client
    36Monitor
  • CVE-2026-120828Memory exhaustion via abandoned far-future read-concern waiters in disaggregated storage
    34Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-120816Nov 10, 2026 · System collection contents readable through a database change stream with showSystemEvents
    9Monitor
  • ← EarlierCVE-2026-120817Nov 10, 2026 · Post-authentication race condition in MongoDB Server geospatial schema validation
    28Monitor
  • Later →CVE-2026-120819Nov 10, 2026 · Use-after-free in Wasm JS-BSON bridge lets read-only users read 24 KiB via $accumulator
    21Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
MongoDB MongoDB Server7.0.48Vendor (CNA)
MongoDB MongoDB Server8.0.37Vendor (CNA)
MongoDB MongoDB Server8.3.16Vendor (CNA)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 13, 2026+2 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-1183830 days apartPre-authentication use-after-free in MongoDB Server replica set primary catch-up
    38Monitor
  • CVE-2026-1208240 days apartPost-authentication use-after-free in MongoDB Server time-series bucket validation
    34Monitor
  • CVE-2026-1208030 days apartMongoDB SBE $locf Window Accumulator Use-After-Free Enables Heap OOB Read and Server Crash
    28Monitor
  • CVE-2026-1208210 days apartPost-authentication use-after-free in MongoDB Server aggregation sub-pipelines
    28Monitor
  • CVE-2026-1208090 days apartHeap use-after-free read via yield-time state save in time-series block unpacking
    24Monitor
  • CVE-2026-1208110 days apartUse-After-Free in MongoDB Server Classic Query Engine Plan Cache Leads to Information Disclosure and Denial of Service
    24Monitor

Bug bounty scope

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Not on record for this CVE: patch commit or PR link · researcher credit.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
X

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

c
free(dev->buf);/* ... another thread is still running ... */process(dev->buf);

Fixed

c
lock(&dev->lock);free(dev->buf);dev->buf = NULL;unlock(&dev->lock);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records