CVE-2025-62168
Description
A Information Disclosure vulnerability has been identified in the Squid web caching proxy. This flaw occurs when the application fails to properly redact sensitive Hypertext Transfer Protocol (HTTP) authentication credentials from an error response. A remote client can exploit this by triggering an error condition, which allows a malicious script to bypass browser security and disclose the username and password a trusted client uses for access. This directly compromises the security of internal application credentials and security tokens, especially when Squid is configured for backend load balancing.
Statement
This vulnerability has rated as having the severity of Important by the Red Hat Product Security team as a successful exploitation may lead to sensitive information stored in the squid cache to be leaked, that may include authentication tokens for applications hosted behind the squid cache.
The leak happens due to squid cache not properly redacting request headers that may contain sensitive information out from error reports containing the request which triggered the error, resulting in a high confidentiality impact. The attacker does not need to have any kind of authentication to exploit this vulnerability.
To a squid instance to be considered vulnerable the email_err_data configuration may need to be turned on in the application configuration file. If the configuration entry is not present, the default behavior is to share such data letting the instance vulnerable.
The default behavior for squid in Red Hat Enterprise Linux distributions is to have email_err_data option enabled.
Mitigation
This vulnerability can be mitigated by disabling debug information in administration mailto links generated by Squid package. This can be accomplished in Red Hat Enterprise Linux by the following steps:
1) With administrative privileges, edit the squid configuration file located at
/etc/squid/squid.conf
2) Add or change this configuration entry to:
email_err_data off
3) Save the configuration file
4) Restart the squid application
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 | 8.6 | 7.5 | 10 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | Low | Low | Low |
| Privileges Required | None | None | None |
| User Interaction | None | None | None |
| Scope | Changed | Unchanged | Changed |
| Confidentiality | High | High | High |
| Integrity Impact | None | None | High |
| Availability Impact | None | None | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Application Data
Often this will either reveal sensitive information which may be used to launch another, more focused attack or disclose private information stored in the server. For example, an attempt to exploit a path traversal weakness (CWE-22) might yield the full pathname of the installed application. In turn, this could be used to select the proper number of ".." sequences to navigate to the targeted file. An attack using SQL injection (CWE-89) might not initially succeed, but an error message could reveal the malformed query, which would expose query logic and possibly even passwords or other sensitive information used within the query.
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