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CVE-2026-13059 is an access control bypass vulnerability affecting MongoDB Server in non‑apiStrict configurations. The flaw stems from insufficient validation of client‑supplied command parameters, which allows an authenticated low‑privilege user to circumvent role‑based query‑level access controls. The issue impacts four core database commands: `find` (read), `update` (modify), `delete` (remove), and `aggregate` (complex data processing).
In a properly configured MongoDB environment, role‑based access controls restrict which documents a user can see or modify based on query filters. For example, a user with a role that only permits access to documents where `{ region: “EU” }` should never be able to read or write documents with { region: "US" }. However, due to inadequate validation of certain command parameters, an attacker can craft maliciously formed commands that cause the server to ignore or misinterpret the intended query‑level filters. The validation failure occurs at the parameter‑parsing stage, where the server trusts client‑supplied values without sufficiently sanitising or verifying them against the user’s role‑based permissions.
The vulnerability is especially dangerous because it does not require elevated privileges—only a valid low‑privilege account is needed. The attack vector is network‑based, with low attack complexity and no user interaction required. The affected commands are fundamental to database operations, meaning an attacker can not only exfiltrate sensitive data but also corrupt or delete protected records. The flaw exists in MongoDB versions 7.0.x before 7.0.39, 8.0.x before 8.0.28, 8.2.x before 8.2.12, and 8.3.x before 8.3.7. It does not affect configurations where `apiStrict` mode is enabled, as that mode enforces stricter parameter validation. MongoDB has assigned this issue the internal tracking ID SERVER‑128433 and released fixed versions on July 22, 2026. The CVSS v4.0 base score is 8.6 (High), with the vector CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N. The weakness is mapped to CWE‑807 (Reliance on Untrusted Inputs in a Security Decision). No public exploits are known at the time of writing, but the technical details are publicly available, making it a high‑priority patch for all affected deployments.
DailyCVE Form:
Platform: MongoDB Server
Version: 7.0<7.0.39/8.0<8.0.28/8.2<8.2.12/8.3<8.3.7
Vulnerability: RBAC Bypass
Severity: High (8.6)
date: 2026-07-22
Prediction: 2026-07-22 (already)
What Undercode Say:
Analytics & Detection Commands
Check MongoDB version
mongod --version
Query current version from the shell
db.version()
List all users and their roles (identify low-privilege accounts)
use admin
db.system.users.find().pretty()
Review role-based query filters for sensitive collections
db.getCollectionInfos({ name: "sensitive_collection" })
Monitor for unusual find/update/delete/aggregate operations
db.adminCommand({ getLog: "global" }) | grep -E "find|update|delete|aggregate"
Enable apiStrict mode as a temporary mitigation (if feasible)
Add to mongod.conf:
setParameter:
apiStrict: true
Restart MongoDB after configuration change
sudo systemctl restart mongod
Verify apiStrict is active
db.adminCommand({ getParameter: 1, apiStrict: 1 })
Exploit:
An attacker with a valid low‑privilege account can send a crafted command to the MongoDB server where the query filter or projection parameters are manipulated to bypass the role‑based restrictions. For example, a user whose role limits reads to `{ region: “EU” }` could modify the `find` command to include an `$or` clause that widens the filter, or supply a malformed BSON object that causes the server to fall back to an unrestricted query. The absence of `apiStrict` mode allows these malformed parameters to be processed without rejection. The attack is remote, requires no special tools beyond a standard MongoDB driver, and can be executed repeatedly to enumerate or modify protected data. No public exploit code has been released, but the technical details are sufficient for a skilled adversary to develop one.
Protection:
- Upgrade immediately to MongoDB 7.0.39, 8.0.28, 8.2.12, or 8.3.7 (or later) as these versions contain the official fix.
- Enable `apiStrict` mode in `mongod.conf` (
setParameter: { apiStrict: true }) if an upgrade is not immediately possible—this mode enforces stricter validation of client parameters and mitigates the bypass. - Restrict low‑privilege user permissions to the minimum necessary and regularly audit role assignments.
- Monitor database logs for anomalous patterns in
find,update,delete, and `aggregate` commands, especially from accounts with low privileges. - Apply network‑level access controls (firewall rules, VPNs) to limit which clients can connect to the MongoDB instance.
- Follow MongoDB’s official advisory (SERVER‑128433) for any additional guidance or backported patches.
Impact:
- Confidentiality: An attacker can read any document in collections they are not authorised to access, leading to data leakage of sensitive information (PII, financial records, trade secrets).
- Integrity: Unauthorised `update` and `delete` operations allow data corruption, deletion, or injection of malicious content, compromising the trustworthiness of the database.
- Multi‑tenancy breakdown: In shared environments, this vulnerability completely breaks the isolation between tenants, as one tenant’s low‑privilege user can access another tenant’s data.
- Compliance violations: Breaches resulting from this flaw may trigger regulatory penalties under GDPR, HIPAA, or other data protection frameworks.
- Business continuity: While availability is not directly affected (CVSS:VA:N), the integrity and confidentiality impacts can lead to significant operational disruption, reputational damage, and financial loss.
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Sources:
Reported By: nvd.nist.gov
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