CVE-2021-22876
Description
It was discovered that libcurl did not remove authentication credentials from URLs when automatically populating the Referer HTTP request header while handling HTTP redirects. This could lead to exposure of the credentials to the server to which requests were redirected.
Mitigation
This issue can be avoided by using at least one of the following recommendations:
* Do not enable automatic generation of Referer headers when redirects are followed. This functionality is not enabled by default. In the curl command line tool, it is enabled using the -e ';auto' or --referer ';auto' command line options. In the libcurl library, it is enabled using the CURLOPT_AUTOREFERER option.
* Do not include authentication credentials in URLs (in the form of https://username:password@example.com), use other methods to provide authentication credentials to curl / libcurl. For the curl command line tool, use -u or --user command line option. For the libcurl library, use CURLOPT_USERPWD or CURLOPT_USERNAME / CURLOPT_PASSWORD options.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 3.7 | 5.3 | 5.3 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | High | Low | Low |
| Privileges Required | None | None | None |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | Low | Low | Low |
| Integrity Impact | None | None | None |
| Availability Impact | None | None | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Application Data
Acknowledgements
Red Hat would like to thank the Curl project for reporting this issue. Upstream acknowledges Viktor Szakats as the original reporter.
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