# CVE-2026-54163

## Summary

- **CVE ID:** CVE-2026-54163
- **Severity:** MEDIUM
- **CVSS Score:** 4.7 (CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N)
- **CWE:** CWE-79, CWE-113
- **Published:** Jul 17, 2026
- **Last Modified:** Jul 20, 2026

## Description

secure_headers manages application of security headers with many safe defaults. Prior to 7.3.0, secure_headers builds the Content-Security-Policy value by stitching directives with ; separators, and build_sandbox_list_directive, build_media_type_list_directive, and build_report_to_directive interpolate caller-supplied strings without scrubbing ;, \r, or \n. When untrusted input reaches SecureHeaders.override_content_security_policy_directives or append APIs for :sandbox, :plugin_types, or :report_to, an attacker can inject a CSP directive such as script-src 'unsafe-inline' * before the legitimate script-src, enabling XSS reachability through these sinks or CSP report exfiltration. This issue is fixed in version 7.3.0.

## Affected Products

- github — secure_headers (< 7.3.0)

## References

- [CNA](https://github.com/github/secure_headers/security/advisories/GHSA-rqq5-2gf9-4w4q)
- [CNA](https://github.com/github/secure_headers/commit/286a79dea80c6a9be4ca93e0f284c923cf77e539)
- [CNA](https://github.com/github/secure_headers/releases/tag/v7.3.0)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.29%
- **EPSS Percentile:** 21.0

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._