Prevent cache poisoning via a Response Content-Type header
Priority LOW 23CWE-435Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · Low
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and GitHub.
Summary
In Symfony before versions 4.4.7 and 5.0.7, when a `Response` does not contain a `Content-Type` header, affected versions of Symfony can fallback to the format defined in the `Accept` header of the request, leading to a possible mismatch between the response's content and `Content-Type` header. When the response is cached, this can prevent the use of the website by other users. This has been patched in versions 4.4.7 and 5.0.7.
Why it matters now
EPSS 0.01297 70th percentileScored 2026-11-07
Fix Fixed symfony/http-foundation (Packagist): 4.4.7, 5.0.7symfony/symfony (Packagist): 4.4.7, 5.0.7
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| symfony | symfony | >= 4.4.0 and < 4.4.7; >= 5.0.0 and < 5.0.7 | — | No fix listed | CNA |
| — | symfony/http-foundation (Packagist) | 4.4.0 to before 4.4.7 | 4.4.7 | Patch available | GHSA-mcx4-f5f5-4859 |
| — | symfony/http-foundation (Packagist) | 5.0.0 to before 5.0.7 | 5.0.7 | Patch available | GHSA-mcx4-f5f5-4859 |
| — | symfony/symfony (Packagist) | 4.4.0 to before 4.4.7 | 4.4.7 | Patch available | GHSA-mcx4-f5f5-4859 |
| — | symfony/symfony (Packagist) | 5.0.0 to before 5.0.7 | 5.0.7 | Patch available | GHSA-mcx4-f5f5-4859 |
- symfony Vendorsymfony Affected >= 4.4.0 and < 4.4.7; >= 5.0.0 and < 5.0.7 Fixed in — No fix listed CNA
- symfony/http-foundation (Packagist) Vendor— Affected 4.4.0 to before 4.4.7 Fixed in 4.4.7 Patch available GHSA-mcx4-f5f5-4859
- symfony/http-foundation (Packagist) Vendor— Affected 5.0.0 to before 5.0.7 Fixed in 5.0.7 Patch available GHSA-mcx4-f5f5-4859
- symfony/symfony (Packagist) Vendor— Affected 4.4.0 to before 4.4.7 Fixed in 4.4.7 Patch available GHSA-mcx4-f5f5-4859
- symfony/symfony (Packagist) Vendor— Affected 5.0.0 to before 5.0.7 Fixed in 5.0.7 Patch available GHSA-mcx4-f5f5-4859
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:* | 4.4.0 to before 4.4.7; 5.0.0 to before 5.0.7 | Vulnerable | sensiolabs |
- cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:* Versions 4.4.0 to before 4.4.7; 5.0.0 to before 5.0.7 Vulnerable ·sensiolabs
Remediation
- Fix · GHSA-mcx4-f5f5-4859 symfony/http-foundation (Packagist) Fixed in 4.4.7 Advisory →
- Fix · GHSA-mcx4-f5f5-4859 symfony/http-foundation (Packagist) Fixed in 5.0.7 Advisory →
- Fix · GHSA-mcx4-f5f5-4859 symfony/symfony (Packagist) Fixed in 4.4.7 Advisory →
- Fix · GHSA-mcx4-f5f5-4859 symfony/symfony (Packagist) Fixed in 5.0.7 Advisory →
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Advisory ·
symfony — FEDORA-2020-fade6a8df7
2 records Highest priority Priority LOW 2 LOW
Other records, highest priority first
- TI-2020-04331 Firewall configured with unanimous strategy was not actually unanimous in symfony/security-httpPriority LOW 38
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2020-5255
- 2026-10-03 Alias added: GHSA-mcx4-f5f5-4859
References
Advisory 4
Other 4
- https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/http-foundation/CVE-2020-5255.yaml
- https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-2020-5255.yaml
- https://lists.fedoraproject.org/archives/list/[email protected]/message/C36JLPHUPKDFAX6D5WYFC4ALO2K7RDUQ
- https://symfony.com/cve-2020-5255
More symfony vulnerabilities
- TI-2024-33775 Ability to change environment from query in symfony/runtime CVSS 3.1HIGH 7.3
- TI-2026-34283 Twig: The `spaceless` filter implicitly marks its output as safe CVSS 4.0MEDIUM 5.1
- TI-2022-07667 Code injection in Twig CVSS 3.1CRITICAL 9.8
- TI-2018-10028 Twig before 2.4.4 allows Server-Side Template Injection (SSTI) via the search search_key… CVSS 3.0CRITICAL 9.8
- TI-2026-35851 Incorrect authorization in symfony CVSS 4.0HIGH 8.7
- TI-2026-35264 Improper input validation in symfony CVSS 4.0HIGH 8.3
Sources
- CVE-2020-5255 · CVE Program
- CVE-2020-5255 · NVD
- FIRST EPSS
- GHSA-mcx4-f5f5-4859 · GitHub Advisory Database · CC BY 4.0
- CVE-2020-5255 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences