What’s Vulnerable › Vulnerabilities
CVE-2021-32762: Integer overflow that can lead to heap overflow in redis-cli, redis-sentinel on some platforms
- Severity: high (CVSS 8.8 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 2.6% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2021-10-04 · updated 2026-06-17
- Weakness: CWE-190
Description
Redis is an open source, in-memory database that persists on disk. The redis-cli command line tool and redis-sentinel service may be vulnerable to integer overflow when parsing specially crafted large multi-bulk network replies. This is a result of a vulnerability in the underlying hiredis library which does not perform an overflow check before calling the calloc() heap allocation function. This issue only impacts systems with heap allocators that do not perform their own overflow checks. Most modern systems do and are therefore not likely to be affected. Furthermore, by default redis-sentinel uses the jemalloc allocator which is also not vulnerable. The problem is fixed in Redis versions 6.2.6, 6.0.16 and 5.0.14.
Affected products
- Debian Linux: 10.0, 11.0
- Fedoraproject Fedora: 33, 34, 35
- NetApp Management Services For Element Software: all versions
- NetApp Management Services For Netapp Hci: all versions
- Oracle Corporation Communications Operations Monitor: 4.3, 4.4, 5.0
- Redis: from 5.0.0 before 5.0.14; from 6.0.0 before 6.0.16; from 6.2.0 before 6.2.6 — fixed in 5.0.14, 6.0.16, 6.2.6
How to fix
Upgrade to a fixed version: Redis 5.0.14, 6.0.16, 6.2.6. Check the vendor advisory for mitigations.
References
- https://github.com/redis/redis/commit/0215324a66af949be39b34be2d55143232c1cb71
- https://github.com/redis/redis/security/advisories/GHSA-833w-8v3m-8wwr
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HTYQ5ZF37HNGTZWVNJD3VXP7I6MEEF42/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VL5KXFN3ATM7IIM7Q4O4PWTSRGZ5744Z/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WR5WKJWXD4D6S3DJCZ56V74ESLTDQRAB/
- https://security.gentoo.org/glsa/202209-17
- https://security.netapp.com/advisory/ntap-20211104-0003/
- https://www.debian.org/security/2021/dsa-5001
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://github.com/redis/redis/commit/0215324a66af949be39b34be2d55143232c1cb71
- https://github.com/redis/redis/security/advisories/GHSA-833w-8v3m-8wwr
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HTYQ5ZF37HNGTZWVNJD3VXP7I6MEEF42/
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