What’s Vulnerable › Vulnerabilities
CVE-2021-41099: Integer overflow issue with strings in Redis
- Severity: high (CVSS 7.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 3.6% 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. An integer overflow bug in the underlying string library can be used to corrupt the heap and potentially result with denial of service or remote code execution. The vulnerability involves changing the default proto-max-bulk-len configuration parameter to a very large value and constructing specially crafted network payloads or commands. The problem is fixed in Redis versions 6.2.6, 6.0.16 and 5.0.14. An additional workaround to mitigate the problem without patching the redis-server executable is to prevent users from modifying the proto-max-bulk-len configuration parameter. This can be done using ACL to restrict unprivileged users from using the CONFIG SET command.
Affected products
- Debian Linux: 10.0, 11.0
- Fedoraproject Fedora: 33, 34, 35
- NetApp Management Services For Element Software And 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/c6ad876774f3cc11e32681ea02a2eead00f2c521
- https://github.com/redis/redis/security/advisories/GHSA-j3cr-9h5g-6cph
- 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/c6ad876774f3cc11e32681ea02a2eead00f2c521
- https://github.com/redis/redis/security/advisories/GHSA-j3cr-9h5g-6cph
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HTYQ5ZF37HNGTZWVNJD3VXP7I6MEEF42/
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