What’s Vulnerable › Vulnerabilities

CVE-2021-32626: Lua scripts can overflow the heap-based Lua stack in Redis

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 16.2% 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-122

Description

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.

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 2.6 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/666ed7facf4524bf6d19b11b20faa2cf93fdf591
• https://github.com/redis/redis/security/advisories/GHSA-p486-xggp-782c
• https://lists.apache.org/thread.html/r75490c61c2cb7b6ae2c81238fd52ae13636c60435abcd732d41531a0%40%3Ccommits.druid.apache.org%3E
• 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/666ed7facf4524bf6d19b11b20faa2cf93fdf591
• https://github.com/redis/redis/security/advisories/GHSA-p486-xggp-782c

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