CVE-2021-21309: Integer overflow on 32-bit systems
First published: Mon Feb 22 2021(Updated: )
An integer overflow was found in Redis. Redis 4.0 or newer uses a configurable limit for the maximum supported bulk input size. The default size is 512MB which is a safe value for all platforms. Authenticated Redis users could increase the bulk input size by changing the "proto-max-bulk-len" configuration parameter, leading to heap corruption and potentially remote code execution.
Credit: security-advisories@github.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Redislabs Redis | >=4.0<5.0.11 | |
| Redislabs Redis | >=6.0.0<6.0.11 |
Remedy
As recommended in the upstream advisory, this issue can be mitigated by preventing clients from directly executing `CONFIG SET`: * Using Redis 6.0 or newer, ACL configuration can be used to block the command. * Using older versions, the `rename-command` configuration directive can be used to rename the command to a random string unknown to users, rendering it inaccessible.
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Reference Links
- https://github.com/redis/redis/commit/c992857618db99776917f10bf4f2345a5fdc78b0
- https://github.com/redis/redis/pull/8522
- https://github.com/redis/redis/security/advisories/GHSA-hgj8-vff2-7cjf
- https://security.gentoo.org/glsa/202103-02
- https://groups.google.com/g/redis-db/c/fV7cI3GSgoQ/m/ocwV-MlzAgAJ
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=1932636
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=1932635
- https://github.com/redis/redis/commit/d32f2e9999ce003bad0bd2c3bca29f64dcce4433
- https://access.redhat.com/errata/RHSA-2021:2461
- https://access.redhat.com/security/cve/cve-2021-21309
- https://access.redhat.com/errata/RHSA-2021:3016
- https://bugzilla.redhat.com/show_bug.cgi?id=1932634
- https://www.cve.org/CVERecord?id=CVE-2021-21309 https://nvd.nist.gov/vuln/detail/CVE-2021-21309 https://github.com/redis/redis/security/advisories/GHSA-hgj8-vff2-7cjf
Frequently Asked Questions
What is CVE-2021-21309?
CVE-2021-21309 is an integer overflow vulnerability found in Redis versions 4.0 or newer.
How can the CVE-2021-21309 vulnerability be exploited?
The CVE-2021-21309 vulnerability can be exploited to corrupt the heap and potentially result in remote code execution.
Which versions of Redis are affected by CVE-2021-21309?
Redis versions 4.0 or newer are affected by CVE-2021-21309.
What is the severity of CVE-2021-21309?
CVE-2021-21309 has a severity rating of 8.8 (high).
How do I fix the CVE-2021-21309 vulnerability?
To fix the CVE-2021-21309 vulnerability, update Redis to version 5.0.11 if using version 5.0.x, or update to version 6.0.11 if using version 6.0.x. Alternatively, update to version 6.2.
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