CVE-2026-34501
Description
A flaw was found in the Redis client in the Apache Portable Runtime Utility (apr-util). A heap buffer overflow can be triggered when the application processes a specially crafted response from a Redis server, resulting in a crash and denial of service.
Statement
The impact of this vulnerability is rated as Moderate. Although the flaw involves a heap buffer overflow and the CVSS base score reflects an unauthenticated network vector, exploitation requires the attacker to control or compromise the Redis server that the application queries. An attacker cannot trigger this condition by sending data directly to the affected application — they must first be in a position to influence Redis responses, either by compromising the Redis backend or performing a man-in-the-middle attack on the connection. Additionally, the overflow does not result in arbitrary code execution; the observed impact is limited to a denial of service. This prerequisite significantly limits real-world exploitability.
Mitigation
Ensure that the Redis server used by the application is deployed in a trusted, network-segregated environment and is not accessible to untrusted parties. Where possible, configure authentication and TLS on the Redis connection to reduce the risk of a compromised or spoofed Redis server.
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 | 7.5 | N/A | 7.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Integrity,Confidentiality,Availability
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
Buffer overflows often can be used to execute arbitrary code, which is usually outside the scope of the product's implicit security policy. This can often be used to subvert any other security service.
Availability
Technical Impact: Modify Memory; DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU)
Buffer overflows generally lead to crashes. Other attacks leading to lack of availability are possible, including putting the product into an infinite loop.
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