CVE-2021-32626
Lua scripts can overflow the heap-based Lua stack in Redis
Exploitation likely. EPSS gives it a 16% chance of exploitation in the next 30 days. A vendor fix is available.
What to do
The vendor has published a fix. Version details are below where the sources state them.
What it is
From the CVE record
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.
In plain language
No plain-language summary for this CVE yet.
Exploitation
Where each signal puts this CVE on the scale from published to confirmed exploited.
- CISA KEV
Not in the catalog. CISA has not confirmed exploitation.
- Public exploits
No public exploit or proof of concept found in the sources we track.
- EPSS
16% chance of exploitation activity in the next 30 days, which ranks it in the 97th percentile of scored CVEs.
Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.
Lifecycle
7 events over 1725 days, from the signal feeds we watch.
- OpenVAS check added
- EPSS band changelow → moderate
- Patch availablerecord updated
- Publishedweakness classified, att&ck mapped
Affected products
And 7 more affected products. See all after sign-in
Technical detail
CVSS 3.1 vector
Open in the CVSS calculatorCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Scored 7.5 by NVD.
How it is reached
- Attack Vector NetworkExploitable remotely over the network without any special conditions
- Attack Complexity HighRequires specific conditions like a race condition or non-default configuration
- Privileges Required LowRequires basic user-level privileges
- User Interaction NoneNo user interaction needed — fully automated exploitation
Scope
- Scope UnchangedImpact is limited to the vulnerable component itself
Impact if exploited
- Confidentiality HighTotal information disclosure — all data in the component is compromised
- Integrity HighTotal loss of integrity — attacker can modify any data in the component
- Availability HighTotal denial of service — the component is completely unavailable
Weaknesses
ATT&CK techniques
Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.
- Initial AccessT1190Exploit Public-Facing Applicationhigh confidence
- Privilege EscalationT1068Exploitation for Privilege Escalationhigh confidence
Sources
References in the record
- github.com/redis/redis/commit/666ed7facf4524bf6d19b11b20faa2cf93fdf591
- github.com/redis/redis/security/advisories/GHSA-p486-xggp-782c
- lists.apache.org/thread.html/r75490c61c2cb7b6ae2c81238fd52ae13636c60435abcd732d41531a0%40%3Ccommits.druid.apache.org%3E
And 18 more references. See all after sign-in
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