CVE-2026-33515
Description
A flaw was found in Squid, a caching proxy for the Web. Due to improper input validation, Squid is vulnerable to an out-of-bounds read when handling Internet Cache Protocol (ICP) traffic. A remote attacker can exploit this by sending invalid ICP requests, potentially receiving small amounts of memory containing sensitive information. This vulnerability is limited to Squid deployments that have explicitly enabled ICP support.
Statement
This flaw in Squid has Moderate impact. It is only exploitable in Red Hat products if Squid is configured to explicitly enable ICP support (i.e., icp_port is set to a non-zero value), which is not the default configuration. This issue cannot be mitigated by icp_access rules.
Mitigation
To mitigate this vulnerability, ensure that Internet Cache Protocol (ICP) support is disabled in Squid. This can be achieved by setting `icp_port` to `0` or commenting out the `icp_port` directive in the `squid.conf` configuration file. After modifying the configuration, the Squid service must be restarted for the changes to take effect.
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).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.3 | 6.5 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | Low | Low | N/A |
| Integrity Impact | None | Low | N/A |
| Availability Impact | None | None | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/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:L/A:N
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
An attacker could get secret values such as cryptographic keys, PII, memory addresses, or other information that could be used in additional attacks.
Confidentiality
Technical Impact: Bypass Protection Mechanism
Out-of-bounds memory could contain memory addresses or other information that can be used to bypass ASLR and other protection mechanisms in order to improve the reliability of exploiting a separate weakness for code execution.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker could cause a segmentation fault or crash by causing memory to be read outside of the bounds of the buffer. This is especially likely when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string.
Other
Technical Impact: Varies by Context
The read operation could produce other undefined or unexpected results.
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