MongoDB Server: Use After Free
CVE-2026-118383 is a critical-severity use after free vulnerability in MongoDB Server from MongoDB, with a CVSS 3.1 base score of 10.0 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 9.0.7, 8.3.16, 8.0.37 as the first without the flaw, so updating MongoDB Server to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.74% chance of exploitation within 30 days, higher than 55% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update MongoDB Server to 9.0.7 or 8.3.16 or 8.0.37 or 7.0.48, whichever matches your release line, or a later version.
- Update Mongodb to 4.4.32 or 5.0.35 or 6.0.30 or 7.0.48, whichever matches your release line, or a later version.
- Read the advisory on jira.mongodb.org for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| MongoDB | MongoDB Server | 9.0.0 up to, but not including, 9.0.7; 8.3.0 up to, but not including, 8.3.16; 8.0.0 up to, but not including, 8.0.37; 7.0.0 up to, but not including, 7.0.48; 6.0.0 up to, but not including, 6.0.30; 5.0.0 up to, but not including, 5.0.35; 4.4.0 up to, but not including, 4.4.32 | 9.0.7, 8.3.16, 8.0.37, 7.0.48, 6.0.30, 5.0.35 |
| MongoDB | Mongodb | 4.4.0 up to, but not including, 4.4.32; 5.0.0 up to, but not including, 5.0.35; 6.0.0 up to, but not including, 6.0.30; 7.0.0 up to, but not including, 7.0.48; 8.0.0 up to, but not including, 8.0.37; 8.3.0 up to, but not including, 8.3.16; 9.0.0 up to, but not including, 9.0.7 | 4.4.32, 5.0.35, 6.0.30, 7.0.48, 8.0.37, 8.3.16 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 9.5 | Critical | CNA (mongodb.com) |
| CVSS 3.1 | 9.0 | Critical | CNA (mongodb.com) |
| CVSS 3.1 | 10.0 | Critical | NVD |
Official description
A use-after-free in the replication component of MongoDB Server can occur when a newly elected replica set primary completes catch-up. The condition can be caused by requests that do not require authentication, and may result in the server terminating unexpectedly or, under certain conditions, arbitrary code execution in the context of the server process. Replica set members are affected, including the shard and config server replica set members of sharded clusters; standalone mongod instances are not.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- jira.mongodb.org/browse/SERVER-138119Issue Tracking
- jira.mongodb.org/browse/SERVER-138175Issue Tracking
Other vulnerabilities in MongoDB Server
- 7.5 High severity
- 8.8 High severity
- 7.1 High severity
- 8.4 High severity
- 7.2 High severity
- 7.4 High severity
Recent Use After Free vulnerabilities
- 7.8 High severity
- 9.8 Critical severity
- 8.4 High severity
- 7.5 High severity
- 7.8 High severity
- 9.8 Critical severity
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