NVD / CVE Program· CNA mongodb

CVE-2026-120803: MongoDB SBE $locf Window Accumulator Use-After-Free Enables Heap OOB Read and Server Crash

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.
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 8.3.16, 9.0.7.

Low priority for now. Upgrade to MongoDB MongoDB Server 8.3.16, 9.0.7 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

A use-after-free issue exists in MongoDB’s SBE (Slot-Based Execution) implementation of a window function accumulator used by certain $setWindowFields aggregation pipelines. Under specific conditions, the accumulator can retain a dangling pointer to memory that has since been freed. When this stale pointer is later dereferenced during serialization of the carried-forward value, it can result in a heap out-of-bounds read that may expose adjacent heap contents and crash the mongod server. An authenticated user with readWrite privileges on a database can trigger this issue by crafting a specific aggregation pipeline.

HighCVSS 7.1 · v4.0—No exploit Fix available

Memory safety

Published: Nov 10, 2026
Updated: Nov 10, 2026
EPSS: —
CWE: CWE-416

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 28 / 40 · 7.1 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · —

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:L/VI:N/VA:H/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.

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

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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
- 9.0.0 and later · before 9.0.7affected · semver
- 8.3.0 and later · before 8.3.16affected · 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-2026-96297Oct 13, 2026 · MongoDB Server may disclose process memory via a crafted `$_internalApplyOplogUpdate` aggregation pipeline
24Monitor
← EarlierCVE-2026-96299Oct 13, 2026 · Missing Authorization Check on Internal Aggregation Stage in MongoDB Server mongos Leads to Denial of Service
28Monitor
Later →CVE-2026-120804Nov 10, 2026 · Credential-handle retention via missing flag set in Windows Kerberos auth handler
32Monitor

Remediation

Which version to upgrade to

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

Product / package	Fixed version	Source
MongoDB MongoDB Server	8.3.16	Vendor (CNA)
MongoDB MongoDB Server	9.0.7	Vendor (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.

PublishedNov 10, 2026
Fix recordedNov 10, 2026same day
TodayNov 10, 2026same day

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

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

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

MongoDBHackerOne · paid

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

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:L/VI:N/VA:H/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

1free(dev->buf);
2/* ... another thread is still running ... */
3process(dev->buf);

Fixed

1lock(&dev->lock);
2free(dev->buf);
3dev->buf = NULL;
4unlock(&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.

Change log

Fix✗ → ✓Nov 10, 2026, 10:07 PM UTC
Exploit maturity— → noneNov 10, 2026, 9:07 PM UTC

For records you follow, these changes also arrive as notifications. →

References

jira.mongodb.org/browse/SERVER-135180

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

All records