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CVE-2026-8336

Post-authentication use-after-free error in $_internalJsEmit and mapreduce commands

7.7 HighFix available

After invoking $_internalJsEmit, which is not intended to be directly accessible, or mapreduce command’s map function in a certain way, an authenticated user can subsequently crash mongod when the server-side JavaScript engine (through $where, $function, mapreduce reduce stage, etc.) is used also in a specific way, resulting in a post-authentication denial-of-service.

This issue impacts MongoDB Server v8.2 versions prior to 8.2.9 and v8.3 versions prior to 8.3.2.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
High
Privileges needed
Low
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
High

Exploit likelihood

0.26%Up 0.2 points since May 13, 2026
90%50%10%1%

What each source reports

CVE List Score used 7.7

Post-authentication use-after-free error in $_internalJsEmit and mapreduce commands

After invoking $_internalJsEmit, which is not intended to be directly accessible, or mapreduce command’s map function in a certain way, an authenticated user can subsequently crash mongod when the server-side JavaScript engine (through $where, $function, mapreduce reduce stage, etc.) is used also in a specific way, resulting in a post-authentication denial-of-service.

This issue impacts MongoDB Server v8.2 versions prior to 8.2.9 and v8.3 versions prior to 8.3.2.

Record
CVE-2026-8336
CVSS 4.0
7.7 HighCVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/AU:N/R:A/V:D/RE:M/U:Red
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-416
Updated
2026-11-02
EUVDEUVD-2026-29893 7.7

After invoking $_internalJsEmit, which is not intended to be directly accessible, or mapreduce command’s map function in a certain way, an authenticated user can subsequently crash mongod when the server-side JavaScript engine (through $where, $function, mapreduce reduce stage, etc.) is used also in a specific way, resulting in a post-authentication denial-of-service.

This issue impacts MongoDB Server v8.2 versions prior to 8.2.9 and v8.3 versions prior to 8.3.2.

Record
EUVD-2026-29893
CVSS 4.0
7.7 HighCVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/AU:N/R:A/V:D/RE:M/U:Red
Updated
2026-11-02
GitHub AdvisoriesGHSA-5f8r-h2c3-xvqc 7.7

After invoking $_internalJsEmit, which is not intended to be directly accessible, or mapreduce...

After invoking $_internalJsEmit, which is not intended to be directly accessible, or mapreduce command’s map function in a certain way, an authenticated user can subsequently crash mongod when the server-side JavaScript engine (through $where, $function, mapreduce reduce stage, etc.) is used also in a specific way, resulting in a post-authentication denial-of-service.

This issue impacts MongoDB Server v7.0 versions prior to 7.0.34, v8.0 versions prior to 8.0.23, v8.2 versions prior to 8.2.9 and v8.3 versions prior to 8.3.2.

Record
GHSA-5f8r-h2c3-xvqc
CVSS 4.0
7.7 HighCVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/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:N/R:A/V:D/RE:M/U:Red
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-416
Updated
2026-11-02
NVD 7.7

After invoking $_internalJsEmit, which is not intended to be directly accessible, or mapreduce command’s map function in a certain way, an authenticated user can subsequently crash mongod when the server-side JavaScript engine (through $where, $function, mapreduce reduce stage, etc.) is used also in a specific way, resulting in a post-authentication denial-of-service.

This issue impacts MongoDB Server v8.2 versions prior to 8.2.9 and v8.3 versions prior to 8.3.2.

Record
CVE-2026-8336
CVSS 4.0
7.7 HighCVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/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:N/R:A/V:D/RE:M/U:Red
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-416
Updated
2026-11-02
OSV 7.7

Post-authentication use-after-free error in $_internalJsEmit and mapreduce commands

After invoking $_internalJsEmit, which is not intended to be directly accessible, or mapreduce command’s map function in a certain way, an authenticated user can subsequently crash mongod when the server-side JavaScript engine (through $where, $function, mapreduce reduce stage, etc.) is used also in a specific way, resulting in a post-authentication denial-of-service.

This issue impacts MongoDB Server v8.2 versions prior to 8.2.9 and v8.3 versions prior to 8.3.2.

Record
CVE-2026-8336
CVSS 4.0
7.7 HighCVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/AU:N/R:A/V:D/RE:M/U:Red
Weakness
CWE-416
Updated
2026-11-02
OSVUBUNTU-CVE-2026-8336 7.7

After invoking $_internalJsEmit, which is not intended to be directly accessible, or mapreduce command’s map function in a certain way, an authenticated user can subsequently crash mongod when the server-side JavaScript engine (through $where, $function, mapreduce reduce stage, etc.) is used also in a specific way, resulting in a post-authentication denial-of-service. This issue impacts MongoDB Server v8.2 versions prior to 8.2.9 and v8.3 versions prior to 8.3.2.

Record
UBUNTU-CVE-2026-8336
CVSS 4.0
7.7 HighCVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/AU:N/R:A/V:D/RE:M/U:Red
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVBIT-mongodb-2026-8336 No score

Post-authentication use-after-free error in $_internalJsEmit and mapreduce commands

After invoking $_internalJsEmit, which is not intended to be directly accessible, or mapreduce command’s map function in a certain way, an authenticated user can subsequently crash mongod when the server-side JavaScript engine (through $where, $function, mapreduce reduce stage, etc.) is used also in a specific way, resulting in a post-authentication denial-of-service.

This issue impacts MongoDB Server v8.2 versions prior to 8.2.9 and v8.3 versions prior to 8.3.2.

Record
BIT-mongodb-2026-8336
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
mongodb
Bitnami
8.2.0 up to 8.2.9, 8.3.0 up to 8.3.2
8.2.98.3.2

History

History
RecordedChangedSources
affected
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-8336 is a high vulnerability (CVSS 7.7) in Mongodb, published May 13, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.26%, the 17th percentile. Fixed in mongodb 8.2.9.

References

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