Prevent cache poisoning via a Response Content-Type header in Symfony

中 4.3CVE-2020-5255 · BIT-symfony-2020-5255 · GHSA-mcx4-f5f5-4859 · 30/03/2020 公開 · 17/06/2026 更新

要点

CVE-2020-5255 は symfony/http-foundation, symfony/symfony, symfony (sensiolabs) に影響する深刻度「中」 (CVSS 4.3) の脆弱性です。
今後30日間に悪用される確率（EPSS）：1.3%（全脆弱性の 70.4% より高い）。
対処：4.4.7, 5.0.7 以降に更新してください。

パッケージ	影響を受けるバージョン	修正済みバージョン
symfony/http-foundation Packagist	`≥ 4.4.0, < 4.4.7≥ 5.0.0, < 5.0.7`	`4.4.75.0.7`
symfony/symfony Packagist	`≥ 4.4.0, < 4.4.7≥ 5.0.0, < 5.0.7`	`4.4.75.0.7`
symfony sensiolabs	`≥ 4.4.0, < 4.4.7≥ 5.0.0, < 5.0.7`	`4.4.75.0.7`

概要

Description

When a Response does not contain a Content-Type header, Symfony falls back 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 lead to a corrupted cache where the cached format is not the right one.

Resolution

Symfony does not use the Accept header anymore to guess the Content-Type.

The patch for this issue is available here for the 4.4 branch.

Credits

I would like to thank Xavier Lacot from JoliCode for reporting & Yonel Ceruto and Tobias Schultze for fixing the issue.

NVD の説明

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.