CVE-2026-81934
Description
A flaw was found in Redis. This vulnerability, a use-after-free, exists within the tlsProcessPendingData() function, which manages the Transport Layer Security (TLS) pending-data list when Redis is configured with TLS support. A remote, unauthenticated attacker could exploit this to execute unauthorized commands with the same privileges as the Redis server.
Statement
This is an Important flaw in Redis, enabling remote, unauthenticated attackers to achieve arbitrary code execution. The vulnerability specifically impacts Redis instances configured with TLS support, which is not enabled by default in Red Hat Enterprise Linux, thereby limiting exposure in standard deployments.
Mitigation
For Redis instances where TLS is enabled, consider disabling TLS if it is not strictly required. Alternatively, restrict network access to the Redis server to trusted clients only, using firewall rules or network access controls, to prevent unauthenticated remote attackers from reaching the vulnerable service. If TLS is enabled, a restart of the Redis service may be required for 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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | N/A | 7.1 |
| Attack Vector | Network | N/A | Adjacent Network |
| Attack Complexity | High | N/A | High |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory
The use of previously freed memory may corrupt valid data, if the memory area in question has been allocated and used properly elsewhere.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If chunk consolidation occurs after the use of previously freed data, the process may crash when invalid data is used as chunk information.
Confidentiality
Technical Impact: Read Memory
Read operations on freed memory can sometimes leak sensitive information instead of causing a crash
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If malicious data is entered before chunk consolidation can take place, it may be possible to take advantage of a write-what-where primitive to execute arbitrary code. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.
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