Vulnerabilities > CVE-2021-32765 - Integer Overflow or Wraparound vulnerability in multiple products
Summary
Hiredis is a minimalistic C client library for the Redis database. In affected versions Hiredis is vulnurable to integer overflow if provided maliciously crafted or corrupted `RESP` `mult-bulk` protocol data. When parsing `multi-bulk` (array-like) replies, hiredis fails to check if `count * sizeof(redisReply*)` can be represented in `SIZE_MAX`. If it can not, and the `calloc()` call doesn't itself make this check, it would result in a short allocation and subsequent buffer overflow. Users of hiredis who are unable to update may set the [maxelements](https://github.com/redis/hiredis#reader-max-array-elements) context option to a value small enough that no overflow is possible.
Vulnerable Configurations
Part | Description | Count |
---|---|---|
Application | Redis
| 17 |
Application | 1 | |
OS | 1 |
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Forced Integer Overflow This attack forces an integer variable to go out of range. The integer variable is often used as an offset such as size of memory allocation or similarly. The attacker would typically control the value of such variable and try to get it out of range. For instance the integer in question is incremented past the maximum possible value, it may wrap to become a very small, or negative number, therefore providing a very incorrect value which can lead to unexpected behavior. At worst the attacker can execute arbitrary code.
References
- https://wiki.sei.cmu.edu/confluence/display/c/MEM07-C.+Ensure+that+the+arguments+to+calloc%28%29%2C+when+multiplied%2C+do+not+wrap
- https://github.com/redis/hiredis/security/advisories/GHSA-hfm9-39pp-55p2
- https://github.com/redis/hiredis/commit/76a7b10005c70babee357a7d0f2becf28ec7ed1e
- https://lists.debian.org/debian-lts-announce/2021/10/msg00007.html
- https://security.netapp.com/advisory/ntap-20211104-0003/
- https://security.gentoo.org/glsa/202210-32