GHSA-mcx4-f5f5-4859 BIT-symfony-2020-5255 CVE-2020-5255
Prevent cache poisoning via a Response Content-Type header in Symfony
- Severity
- 2.6 / 10
- Low · CVSS 3.1
- Exploit chance (EPSS)
- 1.30%
- Chance of exploitation in the next 30 days. Higher than 70.39% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-435 Improper Interaction Between Multiple Correctly-Behaving Entities
- Fix
- Available
- 2 packages have a fixed version
Description
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.
Affected versions
Packagist
| Package | Vulnerable | Fixed in |
|---|---|---|
| symfony/http-foundation | >= 4.4.0, < 4.4.7 |
4.4.7 |
| symfony/http-foundation | >= 5.0.0, < 5.0.7 |
5.0.7 |
| symfony/symfony | >= 4.4.0, < 4.4.7 |
4.4.7 |
| symfony/symfony | >= 5.0.0, < 5.0.7 |
5.0.7 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
symfony/http-foundation Packagist → 4.4.7
- composer
composer require symfony/http-foundation:^4.4.7
symfony/symfony Packagist → 4.4.7
- composer
composer require symfony/symfony:^4.4.7
Severity breakdown
CVSS 3.1 2.6
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:L
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- Low
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
Weakness
CWE-435: Improper Interaction Between Multiple Correctly-Behaving Entities
An interaction error occurs when two entities have correct behavior when running independently of each other, but when they are integrated as components in a larger system or process, they introduce incorrect behaviors that may cause resultant weaknesses.
References
Advisories
Other links
- github.com/symfony/symfony/security/advisories/GHSA-mcx4-f5f5-4859
- github.com/symfony/symfony/commit/dca343442e6a954f96a2609e7b4e9c21ed6d74e6
- github.com/FriendsOfPHP/security-advisories/blob/master/symfony/http-foundation…
- github.com/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-202…
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/C36JL…
- symfony.com/blog/cve-2020-5255-prevent-cache-poisoning-via-a-response-content-ty…
- symfony.com/cve-2020-5255
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-2v3c-qxhr-7vpv Symfony: Unbounded Recursion in the YAML Inline Lexer Lets a Single Document Crash the Process | High | Also affects symfony/symfony |
| GHSA-r925-mgvr-h9cc Symfony: ReDoS in HeaderUtils::split() Reachable Through the Cache-Control Request Header | High | Also affects symfony/http-foundation |
| GHSA-h5x3-xfc9-m39h Symfony: UrlGenerator Dot-Segment Encoding Skips Every Other Chained `../` or `./` → Generated URL Collapses Off-Route Under RFC 3986 Normalization | Medium | Also affects symfony/symfony |
| GHSA-v3wm-qf9p-c549 Symfony: HtmlSanitizer URL Parser Deny Gates Underinclusive: Percent-Encoded BiDi Marks and Unicode Whitespace Bypass Visual-Spoofing Defense | Medium | Also affects symfony/symfony |
| GHSA-rrj9-5q2j-4gvr Symfony: Mailomat Mailer Webhook Parser Reads the HMAC Algorithm from the Request: Signature Algorithm Downgrade | Medium | Also affects symfony/symfony |
| GHSA-38cx-cq6f-5755 Symfony: IpUtils::PRIVATE_SUBNETS Omits IPv6 Transition Forms (6to4, NAT64, Teredo, IPv4-compatible): SSRF Bypass in NoPrivateNetworkHttpClient | High | Also affects symfony/http-foundation |
| GHSA-6h46-9jf5-q59x Symfony: Security Firewall Bypass via failure_forward Subrequest: Unauthenticated Access to access_control-Protected GET Routes | High | Also affects symfony/symfony |
| GHSA-x5qj-865h-mgvm Symfony: HtmlSanitizer UrlAttributeSanitizer Misses URL Attributes | Medium | Also affects symfony/symfony |
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