Vulnerability Report

CVE-2020-5255

Title: Content-Type header mismatch leads to caching issues in Symfony

Input Validation Error

Proof Of Concept

No public PoC currently indexed for CVE-2020-5255.

CWE Category CWE-20
Published Date Mar 30, 2020
Modified Date Jun 17, 2026
Exploit Status Not Found
Score 2.6 CVSS v3.1
Exploit Probability (EPSS)
1.30%

Vulnerability Summary

CVE-2020-5255: 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.

Impacted Vendors

S
sensiolabs 1
A
auth0 1

Reference Links

https://github.com/symfony/symfony/commit/dca343442e6a954f96a2609e7b4e9c21ed6d74e6 https://github.com/symfony/symfony/security/advisories/GHSA-mcx4-f5f5-4859 https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/C36JLPHUPKDFAX6D5WYFC4ALO2K7RDUQ/ https://symfony.com/blog/cve-2020-5255-prevent-cache-poisoning-via-a-response-content-type-header https://github.com/symfony/symfony/commit/dca343442e6a954f96a2609e7b4e9c21ed6d74e6 https://github.com/symfony/symfony/security/advisories/GHSA-mcx4-f5f5-4859 https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/C36JLPHUPKDFAX6D5WYFC4ALO2K7RDUQ/ https://symfony.com/blog/cve-2020-5255-prevent-cache-poisoning-via-a-response-content-type-header
CVSS v3.1
Source Entity [email protected]
Severity LOW
2.6
Attack Vector
NETWORK
Complexity
HIGH
Privileges
N/A
Interaction
REQUIRED
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:L
CVSS v3.1
Source Entity [email protected]
Severity MEDIUM
4.3
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
CVSS v2.0
Source Entity [email protected]
Severity MEDIUM
4.0
Access Vector
N/A
Authentication
N/A
RAW VECTOR AV:N/AC:L/Au:S/C:N/I:N/A:P

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2020-5255 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data or affected products updated.

PUBLISHED

Vulnerability first announced in NVD.

Attack Vector Matrix

Access Vector NETWORK
Complexity HIGH
Privileges N/A
Interaction REQUIRED
CVSS Vector String CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:L

Affected Stack

No specific products linked.