CVE-2020-15094: Symfony/http kernel Remote Code Execution Vulnerability

HIGH
Advisory Identifier: GHSA-754h-5r27-7x3r
CVSS 8.0
CWE-212
Published
Advisory Summary

CVE-2020-15094 is a HIGH (CVSS 8.0) remote code execution vulnerability (CWE-212: Improper Removal of Sensitive Information Before Storage or Transfer) affecting Symfony/http kernel libraries in the Packagist ecosystem. The issue involves rce in symfony. Remediation is available by upgrading affected packages to version 4.4.13, 5.1.5.

CVE-2020-15094 at a Glance

CVE Identifier CVE-2020-15094
GHSA Identifier GHSA-754h-5r27-7x3r
Severity HIGH
CVSS v3.1 Base Score 8.0
CWE Classification CWE-212: Improper Removal of Sensitive Information Before Storage or Transfer
Affected Product Symfony/http kernel
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 8.0

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required Low (PR:L)
User Interaction Required (UI:R)
Scope Changed (S:C)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2020-15094

To remediate this vulnerability, upgrade all affected Symfony/http kernel dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

symfony/http-kernel fixed: 4.4.13
Upgrade symfony/http-kernel to 4.4.13
symfony/http-kernel fixed: 5.1.5
Upgrade symfony/http-kernel to 5.1.5
symfony/symfony fixed: 4.4.13
Upgrade symfony/symfony to 4.4.13
symfony/symfony fixed: 5.1.5
Upgrade symfony/symfony to 5.1.5
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release:

inspect dependencies for symfony/http-kernel

How to Check if You Are Affected

To determine whether your application is affected by CVE-2020-15094, inspect your project dependencies for Symfony/http kernel:

inspect dependencies for symfony/http-kernel

Analyze the terminal output to locate any version of Symfony/http kernel in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 4.4.13), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-212: Improper Removal of Sensitive Information Before Storage or Transfer, where the product stores, transfers, or shares a resource that contains sensitive information, but it does not properly remove that information before the product makes the resource available to unauthorized actors. In Symfony/http kernel, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

Description ----------- The `CachingHttpClient` class from the HttpClient Symfony component relies on the `HttpCache` class to handle requests. `HttpCache` uses internal headers like `X-Body-Eval` and `X-Body-File` to control the restoration of cached responses. The class was initially written with surrogate caching and ESI support in mind (all HTTP calls come from a trusted backend in that scenario). But when used by `CachingHttpClient` and if an attacker can control the response for a request being made by the `CachingHttpClient`, remote code execution is possible. Resolution ---------- HTTP headers designed for internal use in `HttpCache` are now stripped from remote responses before being passed to `HttpCache`. The patch for this issue is available [here](https://github.com/symfony/symfony/commit/d9910e0b33a2e0f993abff41c6fbc86951b66d78) for the 4.4 branch. Credits ------- I would like to thank Matthias Pigulla (webfactory GmbH) for reporting and fixing the issue.

CVE-2020-15094 Affected Symfony/http kernel Versions

4 component(s)
Fixed Versions:
4.4.135.1.5
Product / Package Ecosystem Affected Versions Fixed Version
symfony/http-kernel
Packagist
≥ 4.3.0
< 4.4.13
4.4.13
symfony/http-kernel
Packagist
≥ 5.0.0
< 5.1.5
5.1.5
symfony/symfony
Packagist
≥ 4.3.0
< 4.4.13
4.4.13
symfony/symfony
Packagist
≥ 5.0.0
< 5.1.5
5.1.5

References

Frequently Asked Questions

What is CVE-2020-15094?
CVE-2020-15094 is a security vulnerability in Symfony/http kernel involving RCE in Symfony under CWE-212: Improper Removal of Sensitive Information Before Storage or Transfer.
Which Symfony/http kernel versions are affected?
Affected versions include releases prior to 4.4.13, 5.1.5 across affected packages: symfony/http-kernel, symfony/symfony.
What version fixes CVE-2020-15094?
Upgrading to 4.4.13, 5.1.5 (or the latest patched release for your respective branch) resolves the vulnerability.
Is symfony/http-kernel affected?
Yes, symfony/http-kernel is affected in releases prior to 4.4.13, 5.1.5. Upgrade your dependency to 4.4.13, 5.1.5 or later.
Is symfony/symfony affected?
Yes, symfony/symfony is affected in releases prior to 4.4.13, 5.1.5. Upgrade your dependency to 4.4.13, 5.1.5 or later.
What is the CVSS score of CVE-2020-15094?
CVE-2020-15094 has a CVSS v3.1 base score of 8.0 (HIGH) with vector string CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H.
What CWE is associated with CVE-2020-15094?
CVE-2020-15094 is classified under CWE-212: Improper Removal of Sensitive Information Before Storage or Transfer (The product stores, transfers, or shares a resource that contains sensitive information, but it does not properly remove that information before the product makes the resource available to unauthorized actors.).
How can I check Packagist dependencies for CVE-2020-15094?
Run the dependency tree command: 'inspect dependencies for symfony/http-kernel'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
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  "id" : "GHSA-754h-5r27-7x3r",
  "modified" : "2023-01-24T18:07:50Z",
  "published" : "2020-09-02T17:29:56Z",
  "aliases" : [ "CVE-2020-15094" ],
  "summary" : "RCE in Symfony",
  "details" : "Description\n-----------\n\nThe `CachingHttpClient` class from the HttpClient Symfony component relies on the `HttpCache` class to handle requests. `HttpCache` uses internal headers like `X-Body-Eval` and `X-Body-File` to control the restoration of cached responses. The class was initially written with surrogate caching and ESI support in mind (all HTTP calls come from a trusted backend in that scenario). But when used by `CachingHttpClient` and if an attacker can control the response for a request being made by the `CachingHttpClient`, remote code execution is possible.\n\nResolution\n----------\n\nHTTP headers designed for internal use in `HttpCache` are now stripped from remote responses before being passed to `HttpCache`.\n\nThe patch for this issue is available [here](https://github.com/symfony/symfony/commit/d9910e0b33a2e0f993abff41c6fbc86951b66d78) for the 4.4 branch.\n\nCredits\n-------\n\nI would like to thank Matthias Pigulla (webfactory GmbH) for reporting and fixing the issue.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H"
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    "type" : "WEB",
    "url" : "https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/http-kernel/CVE-2020-15094.yaml"
  }, {
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    "url" : "https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-2020-15094.yaml"
  }, {
    "type" : "PACKAGE",
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  }, {
    "type" : "WEB",
    "url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/HNGUWOEETOFVH4PN3I3YO4QZHQ4AUKF3"
  }, {
    "type" : "WEB",
    "url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VAQJXAKWPMWB7OL6QPG2ZSEQZYYPU5RC"
  }, {
    "type" : "WEB",
    "url" : "https://packagist.org/packages/symfony/http-kernel"
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  }, {
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  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-212" ],
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    "github_reviewed_at" : "2020-09-02T17:29:29Z",
    "nvd_published_at" : "2020-09-02T18:15:00Z"
  }
}