CVE-2025-49844
Description
A vulnerability found in Redis where a flaw in the Lua scripting engine can trigger a use-after-free condition. An authenticated attacker can exploit this by running a specially crafted Lua script, potentially resulting in remote code execution (RCE) within the Redis process.
Statement
This vulnerability should be rated Important rather than Moderate because it introduces a memory-safety defect in Redis’s Lua subsystem that can be weaponized for remote code execution (RCE). An authenticated actor with permission to run Lua can craft scripts that trigger a use-after-free in the parser/stack-management code, giving precise control over freed memory and enabling arbitrary code execution inside the redis-server process. That risk is fundamentally different from a typical moderate issue (e.g., a crash or limited denial-of-service): successful exploitation directly compromises the server runtime and all in-memory contents—cached data, session tokens, and application state—rather than merely disrupting service. Because Redis commonly runs with elevated privileges and is a trusted core component in application architectures, an RCE in the server process undermines confidentiality, integrity, and availability across dependent services. Authenticated attackability, trivial exploitation via standard commands (EVAL/EVALSHA), and the potential for full-process compromise elevate CVE-2025-49844 to Important severity.
This flaw exists only in the Redis server implementation;
Redis client libraries (Python, Node.js, Rust, etc.) are not affected by this vulnerability, and it only exists in the Redis server’s embedded Lua engine where scripts execute. Client libraries merely transmit EVAL/EVALSHA to the server.
Red Hat Satellite does not ship the Redis server, and the Redis client libraries it includes (such as python-redis, python-aioredis and rubygem-redis) are not impacted by this vulnerability. While Satellite consume the Redis package from the underlying RHEL system, which is affected, the Redis service in Satellite is bound only to the local interface and is accessible solely by internal components like Pulp and Dynflow. Since vulnerability requires sending crafted Lua payloads to the Redis command interface, and no external or untrusted clients can connect, the effective exposure within Satellite is nullified.
Mitigation
No mitigation is currently available that meets Red Hat Product Security’s standards for usability, deployment, applicability, or stability.
To reduce the risk, restricting network access to trusted hosts, enforcing strong authentication and protected-mode, disabling or limiting Lua scripting where possible can be beneficial and apply least-privilege ACLs to reduce who can run scripting commands, keep instances non-public with firewalls/VPCs, and follow Redis hardening guidance to minimize exposure.
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 | 8.8 | 9.9 | 9.9 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | Low | Low | Low |
| Privileges Required | Low | Low | Low |
| User Interaction | None | None | None |
| Scope | Unchanged | Changed | Changed |
| Confidentiality | High | High | High |
| Integrity Impact | High | High | High |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Red Hat CVSS v3 Score Explanation
This vulnerability requires low privileges (PR:L), involves no user interaction (UI:N), and has Scope: Unchanged (S:U), meaning the exploit does not impact components outside the vulnerable system’s security boundary. Although the confidentiality (C:H), integrity (I:H), and availability (A:H) impacts are high, the lack of scope change keeps the score at 8.8. Red Hat considers such flaws "Important", not "Critical", because they cannot be exploited by unauthenticated remote attackers and do not enable full system compromise across boundaries—criteria required for a "Critical" rating under Red Hat’s security model.
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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