redis redis CVE-2021-32626 vulnerability in Redis and Other Products
Published on October 4, 2021

Lua scripts can overflow the heap-based Lua stack in Redis

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Redis is an open source, in-memory database that persists on disk. In affected versions specially crafted Lua scripts executing in Redis can cause the heap-based Lua stack to be overflowed, due to incomplete checks for this condition. This can result with heap corruption and potentially remote code execution. This problem exists in all versions of Redis with Lua scripting support, starting from 2.6. The problem is fixed in versions 6.2.6, 6.0.16 and 5.0.14. For users unable to update an additional workaround to mitigate the problem without patching the redis-server executable is to prevent users from executing Lua scripts. This can be done using ACL to restrict EVAL and EVALSHA commands.

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Vulnerability Analysis

CVE-2021-32626 is exploitable with network access, and requires small amount of user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to be very high.

Attack Vector:
NETWORK
Attack Complexity:
HIGH
Privileges Required:
LOW
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
HIGH
Integrity Impact:
HIGH
Availability Impact:
HIGH

Weakness Types

Heap-based Buffer Overflow

A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

What is a Memory Corruption Vulnerability?

The software writes data past the end, or before the beginning, of the intended buffer. Typically, this can result in corruption of data, a crash, or code execution. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent write operation then produces undefined or unexpected results.

CVE-2021-32626 has been classified to as a Memory Corruption vulnerability or weakness.


Products Associated with CVE-2021-32626

You can be notified by email with stack.watch whenever vulnerabilities like CVE-2021-32626 are published in these products:

Redis
 
Fedora Project Fedora
 
Management Services Element Software Netapp Hci
 
NetApp Hci
 
NetApp Management Services Element Software
 
Debian Linux
 
Management Services Netapp Hci
 
Oracle Communications Operations Monitor
 

Affected Versions

redis:

Exploit Probability

EPSS
1.27%
Percentile
79.24%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.