Vulnerability Details : CVE-2021-41267
Symfony/Http-Kernel is the HTTP kernel component for Symfony, a PHP framework for web and console applications and a set of reusable PHP components. Headers that are not part of the "trusted_headers" allowed list are ignored and protect users from "Cache poisoning" attacks. In Symfony 5.2, maintainers added support for the `X-Forwarded-Prefix` headers, but this header was accessible in SubRequest, even if it was not part of the "trusted_headers" allowed list. An attacker could leverage this opportunity to forge requests containing a `X-Forwarded-Prefix` header, leading to a web cache poisoning issue. Versions 5.3.12 and later have a patch to ensure that the `X-Forwarded-Prefix` header is not forwarded to subrequests when it is not trusted.
Products affected by CVE-2021-41267
- cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
Exploit prediction scoring system (EPSS) score for CVE-2021-41267
0.44%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 60 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2021-41267
| Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
|---|---|---|---|---|---|---|
|
4.3
|
MEDIUM | AV:N/AC:M/Au:N/C:N/I:P/A:N |
8.6
|
2.9
|
NIST | |
|
6.5
|
MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N |
2.8
|
3.6
|
GitHub, Inc. |
CWE ids for CVE-2021-41267
-
The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.Assigned by: security-advisories@github.com (Primary)
References for CVE-2021-41267
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https://github.com/symfony/symfony/commit/95dcf51682029e89450aee86267e3d553aa7c487
Fix missing extra trusted header in sub-request · symfony/symfony@95dcf51 · GitHubPatch;Third Party Advisory
-
https://github.com/symfony/symfony/security/advisories/GHSA-q3j3-w37x-hq2q
Webcache Poisoning via X-Forwarded-Prefix and sub-request · Advisory · symfony/symfony · GitHubPatch;Third Party Advisory
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https://github.com/symfony/symfony/releases/tag/v5.3.12
Release v5.3.12 · symfony/symfony · GitHubRelease Notes;Third Party Advisory
-
https://github.com/symfony/symfony/pull/44243
Release v5.3.12 by fabpot · Pull Request #44243 · symfony/symfony · GitHubPatch;Third Party Advisory
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