CVE-2026-81525 — Cross-tenant database retargeting via dot/NUL injection in namespace strings in the PHP Driver
The MongoDB client library for PHP does not sufficiently sanitize special elements in application-supplied namespace identifiers before using them to construct the target namespace for database operations. An application that incorporates untrusted text into these identifiers may have operations silently directed at a different storage location than the one the application intended.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- Technical severity (high)+6
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Mongodb Php Driver, Mongodb PHP Extension, Mongodb Php Library).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes, errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Mongodb | Php Driver | < 1.21.6≥ 2.0.0 and < 2.4.1 | Vulnerable | NIST National Vulnerability Database |
| Mongodb | PHP Extension | < 1.21.6≥ 2.0.0 and < 2.4.1 | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Mongodb | Php Library | < 1.21.4≥ 2.0.0 and < 2.4.1 | Vulnerable | NIST National Vulnerability Database |
| Mongodb | Php Library | < 1.21.4≥ 2.0.0 and < 2.4.1 | Vulnerable | CVE Program (cve.org) e CISA ADP |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 8.6 | CVSS 4.0 | High | — | — | cna@mongodb.com via NIST National Vulnerability Database |
| 8.6 | CVSS 4.0 | High | — | — | mongodb via CVE Program (cve.org) e CISA ADP |
| 8.1 | CVSS 3.1 | High | 2.8 | 5.2 | cna@mongodb.com via NIST National Vulnerability Database |
| 8.1 | CVSS 3.1 | High | — | — | mongodb via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N (score shown at the top: cna@mongodb.com) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · mongodb/php library, mongodb/php extension
- SSVC assessment updated
- Record published
- CVSS changed · 8.1
- Source status changed · → Analyzed
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 15, 2026 – Oct 15, 2026
References
5 on the record
Elsewhere on this site
Related CVEs (same products)
- Medium CVE-2026-106436 Application denial of service and data truncation via unchecked BSON append failures in MongoDB PHP Driver 7d
- High CVE-2026-106432 Heap buffer overflow via 32-bit string-length truncation in MongoDB PHP Driver 7d
- Medium CVE-2026-96745 PHP object injection via unsuppressible __pclass class inference in command monitoring events 21d
- High CVE-2026-88023 GridFS data disclosure and deletion via query-operator injection in file IDs in the MongoDB PHP Library Sep 10, 2026
- Medium CVE-2026-84968 Heap out-of-bounds read via corrupt nested BSON in field path error message Sep 3, 2026
- High CVE-2026-6811 PHP Stack Exhaustion May 14, 2026
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No FIRST EPSS score.
- No fixed version, patch or mitigation documented.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-81525 is "Cross-tenant database retargeting via dot/NUL injection in namespace strings in the PHP Driver", rated High. It affects Php Driver (Mongodb); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 8.1 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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