How severe is CVE-2020-15148?

CVE-2020-15148 has a CVSS score of 10/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2020-15148?

CVE-2020-15148 affects the following packages: yiisoft/yii2 (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2020-15148?

Update yiisoft/yii2 to version 2.0.38 or later. Run your dependency manager's update command and verify no transitive dependencies pin the vulnerable version. Use O3 Security's SCA scanner to confirm the fix is applied across your entire dependency tree.

Is CVE-2020-15148 actively exploited in the wild?

Yes. There are 4 known exploit references for CVE-2020-15148, including 2 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2020-15148?

CVE-2020-15148 has an EPSS (Exploit Prediction Scoring System) score of 93.4%, placing it in the 100th 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. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

What type of vulnerability is CVE-2020-15148?

CVE-2020-15148 is classified as Deserialization of Untrusted Data (CWE-502). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

Is there exploit tooling available for CVE-2020-15148?

A Nuclei detection template exists for CVE-2020-15148, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2020-15148 published, and has it been updated?

CVE-2020-15148 was published on September 15, 2020 and was last updated on April 10, 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

CVE-2020-15148

CRITICAL

Unsafe deserialization in Yii 2

Also known asGHSA-699q-wcff-g9mj

Published

Sep 15, 2020

Updated

Apr 10, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

4 known

EPSS Exploitation Probability

via FIRST.org ↗

93.4%probability of exploitation in next 30 days

Very High Risk100th percentile0.00%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

🐘yiisoft/yii2

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

Yii 2 (yiisoft/yii2) before version 2.0.38 is vulnerable to remote code execution if the application calls unserialize() on arbitrary user input. This is fixed in version 2.0.38. A possible workaround without upgrading is available in the linked advisory.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`yiisoft/yii2`	all versions	2.0.38

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Yii 2 (yiisoft/yii2) before version 2.0.38 is vulnerable to remote code …

github.comGithubSep 2020

Yii 2 (yiisoft/yii2) before version 2.0.38 is vulnerable to remote code …

github.comGithubOct 2020

Frequently Asked Questions

Yii 2 (yiisoft/yii2) before version 2.0.38 is vulnerable to remote code execution if the application calls `unserialize()` on arbitrary user input. This is fixed in version 2.0.38. A possible workaround without upgrading is available in the linked advisory.

O3 Security · Impact-Aware SCA

Is CVE-2020-15148 in your stack?

O3 detects CVE-2020-15148 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my stack How O3 SCA works