MongoDB Server: Out-of-bounds Read
CVE-2026-18688 is a high-severity out-of-bounds read vulnerability in MongoDB Server from MongoDB, with a CVSS 3.1 base score of 7.1 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists versions 8.3.8, 8.0.29, 7.0.40 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 0.4% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update MongoDB Server to 8.3.8 or 8.0.29 or 7.0.40, whichever matches your release line, or a later version.
- Update Mongodb to 7.0.40 or 8.0.29 or 8.3.8, whichever matches your release line, or a later version.
- Read the advisory on jira.mongodb.org for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| MongoDB | MongoDB Server | 8.3.0 up to, but not including, 8.3.8; 8.0 up to, but not including, 8.0.29; 7.0 up to, but not including, 7.0.40 | 8.3.8, 8.0.29, 7.0.40 |
| MongoDB | Mongodb | 7.0.0 up to, but not including, 7.0.40; 8.0.0 up to, but not including, 8.0.29; 8.2.0 through 8.2.12; 8.3.0 up to, but not including, 8.3.8; 9.0.0; 9.1.0 | 7.0.40, 8.0.29, 8.3.8 |
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
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- LowSome restricted data can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H. Scored by CNA (mongodb.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 7.1 | High | CNA (mongodb.com) |
| CVSS 3.1 | 7.1 | High | CNA (mongodb.com) |
Official description
An issue in MongoDB Server's aggregation framework could allow an authenticated user to trigger an out-of-bounds memory read by providing a specially formed numeric parameter in a certain aggregation pipeline stage. This could result in a server crash (denial of service) and may potentially expose a limited amount of memory contents.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Out-of-bounds Read
The product reads data past the end, or before the beginning, of the intended buffer.
How developers prevent this class of flaw
- Use a language that provides appropriate memory abstractions.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- jira.mongodb.org/browse/SERVER-129617Issue Tracking
Other vulnerabilities in MongoDB Server
- 7.5 High severity
- 8.8 High severity
- 7.1 High severity
- 10.0 Critical severity
- 8.4 High severity
- 7.2 High severity
Recent Out-of-bounds Read vulnerabilities
- 7.1 High severity
- 7.0 High severity
- 8.8 High severity
- 7.5 High severity
- 7.8 High severity
- 7.8 High severity
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