CVE-2021-41267
What it is
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.
At a glance
- Exploitability
- Can be exploited over the network without logging in, but needs a user to act. High risk of data tampering.
- Exploit odds
- 1.3% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 1.3% in the next 30 days (EPSS).
- Severity: 6.5 MEDIUM (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 1.3% · EPSS, next 30 days
- Weakness
- CWE-444
- Record status
- Modified
Affected
- Sensiolabs Symfony < 5.3.12
Attack profile CVSS 3.1 · 6.5
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2021-41267.md and follow it. Check whether this project is affected by CVE-2021-41267. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://github.com/symfony/symfony/commit/95dcf51682029e89450aee86267e3d553aa7c487
- https://github.com/symfony/symfony/pull/44243
- https://github.com/symfony/symfony/releases/tag/v5.3.12
- https://github.com/symfony/symfony/security/advisories/GHSA-q3j3-w37x-hq2q
- https://github.com/symfony/symfony/commit/95dcf51682029e89450aee86267e3d553aa7c487
- https://github.com/symfony/symfony/pull/44243
- https://github.com/symfony/symfony/releases/tag/v5.3.12
- https://github.com/symfony/symfony/security/advisories/GHSA-q3j3-w37x-hq2q
References
- https://github.com/symfony/symfony/commit/95dcf51682029e89450aee86267e3d553aa7c487
- https://github.com/symfony/symfony/pull/44243
- https://github.com/symfony/symfony/releases/tag/v5.3.12
- https://github.com/symfony/symfony/security/advisories/GHSA-q3j3-w37x-hq2q
- https://github.com/symfony/symfony/commit/95dcf51682029e89450aee86267e3d553aa7c487
- https://github.com/symfony/symfony/pull/44243
- https://github.com/symfony/symfony/releases/tag/v5.3.12
- https://github.com/symfony/symfony/security/advisories/GHSA-q3j3-w37x-hq2q