How severe is CVE-2026-81525?

No CVSS score has been assigned to CVE-2026-81525 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-81525?

CVE-2026-81525 affects the following packages: mongodb/mongodb (Packagist), mongodb/mongodb (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2026-81525?

Update mongodb/mongodb to 1.21.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-81525 is resolved across your whole dependency graph.

How do I detect CVE-2026-81525 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mongodb/mongodb, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-81525 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2026-81525 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-81525 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-81525?

CVE-2026-81525 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 40th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-81525?

CVE-2026-81525 is classified as CWE-943 (CWE-943). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-81525 published, and has it been updated?

CVE-2026-81525 was published on August 27, 2026 and was last updated on October 1, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

Not in CISA KEV

CVE-2026-81525 — mongodb

Fix: mongodb/mongo-php-library#1967

CVE-2026-81525 is a CWE-943 vulnerability in mongodb/mongodb. A fix is available for mongodb/mongodb — see the affected versions and patch details below.

Cross-tenant database retargeting via dot/NUL injection in namespace strings in the PHP Driver

Also known asGHSA-65fr-j4p9-vc33

Published

Aug 27, 2026

Updated

Oct 1, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Oct 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs40th percentile — riskier than 40% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

2 pkgs affected

🐘mongodb/mongodb🐘mongodb/mongodb

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

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.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`mongodb/mongodb`	all versions	1.21.4`composer require mongodb/mongodb:^1.21.4`
🐘Packagist	`mongodb/mongodb`	≥ 2.0.0&&< 2.4.1	2.4.1`composer require mongodb/mongodb:^2.4.1`

Affected Products

2 products · 4 configurations

Application

php drivermongodb

≥ 2.0.0 && < 2.4.1

range

Application

php librarymongodb

≥ 2.0.0 && < 2.4.1

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mongodb/mongodb, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update mongodb/mongodb to 1.21.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-81525 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.