CVE-2021-21309
published 2021-02-26CVE-2021-21309: Redis is an open-source, in-memory database that persists on disk. In affected versions of Redis an integer overflow bug in 32-bit Redis version 4.0 or newer…
PriorityP260high8.8CVSS 3.1
AVNACLPRLUINSUCHIHAH
EPSS
4.70%
90.7th percentile
Redis is an open-source, in-memory database that persists on disk. In affected versions of Redis an integer overflow bug in 32-bit Redis version 4.0 or newer could be exploited to corrupt the heap and potentially result with remote code execution. Redis 4.0 or newer uses a configurable limit for the maximum supported bulk input size. By default, it is 512MB which is a safe value for all platforms. If the limit is significantly increased, receiving a large request from a client may trigger several integer overflow scenarios, which would result with buffer overflow and heap corruption. We believe this could in certain conditions be exploited for remote code execution. By default, authenticated Redis users have access to all configuration parameters and can therefore use the “CONFIG SET proto-max-bulk-len” to change the safe default, making the system vulnerable. **This problem only affects 32-bit Redis (on a 32-bit system, or as a 32-bit executable running on a 64-bit system).** The problem is fixed in version 6.2, and the fix is back ported to 6.0.11 and 5.0.11. Make sure you use one of these versions if you are running 32-bit Redis. An additional workaround to mitigate the problem without patching the redis-server executable is to prevent 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. Please note that this workaround may have an additional impact on users or operational systems that expect `CONFIG SET` to behave in certain ways.
Affected
25 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | redis | < redis 5:6.0.11-1 (bookworm) | redis 5:6.0.11-1 (bookworm) |
| msrc | cbl_mariner_1.0_arm | — | — |
| msrc | cbl_mariner_1.0_x64 | — | — |
| msrc | cbl_mariner_2.0_arm | — | — |
| msrc | cbl_mariner_2.0_x64 | — | — |
| msrc | redis-5.0.5-6.cm1.aarch64.rpm_on_cbl_mariner_1.0_arm | — | — |
| msrc | redis-5.0.5-6.cm1.x86_64.rpm_on_cbl_mariner_1.0_x64 | — | — |
| msrc | redis-6.2.6-1.cm2.aarch64.rpm_on_cbl_mariner_2.0_arm | — | — |
| msrc | redis-6.2.6-1.cm2.x86_64.rpm_on_cbl_mariner_2.0_x64 | — | — |
| msrc | redis-debuginfo-5.0.5-6.cm1.aarch64.rpm_on_cbl_mariner_1.0_arm | — | — |
| msrc | redis-debuginfo-5.0.5-6.cm1.x86_64.rpm_on_cbl_mariner_1.0_x64 | — | — |
| msrc | redis-debuginfo-6.2.6-1.cm2.aarch64.rpm_on_cbl_mariner_2.0_arm | — | — |
| msrc | redis-debuginfo-6.2.6-1.cm2.x86_64.rpm_on_cbl_mariner_2.0_x64 | — | — |
| redis | redis | < 5.0.11 | 5.0.11 |
| redis | redis | — | — |
| redis | redis | >= 0 < 5:6.0.11-1 | 5:6.0.11-1 |
| redis | redis | >= 0 < 5:6.0.11-1 | 5:6.0.11-1 |
| redis | redis | >= 0 < 5:6.0.11-1 | 5:6.0.11-1 |
| redis | redis | >= 0 < 5:6.0.11-1 | 5:6.0.11-1 |
| redis | redis | >= 0 < 2:2.8.4-2ubuntu0.2+esm2 | 2:2.8.4-2ubuntu0.2+esm2 |
| redis | redis | >= 0 < 2:3.0.6-1ubuntu0.4+esm1 | 2:3.0.6-1ubuntu0.4+esm1 |
| redis | redis | >= 0 < 5:4.0.9-1ubuntu0.2+esm3 | 5:4.0.9-1ubuntu0.2+esm3 |
| redis | redis | >= 0 < 5:5.0.7-2ubuntu0.1+esm1 | 5:5.0.7-2ubuntu0.1+esm1 |
| redislabs | redis | >= 4.0 < 5.0.11 | 5.0.11 |
| redislabs | redis | >= 6.0.0 < 6.0.11 | 6.0.11 |
Detection & IOCsextracted from sources · hover to see the quote
- →Monitor Redis traffic for oversized bulk input requests (significantly exceeding 512MB) sent to 32-bit Redis instances, which may indicate exploitation of the integer overflow ↗
- →Alert on execution of CONFIG SET commands directly by Redis clients; block or rename the command using ACL (Redis 6.0+) or rename-command directive (older versions) as a detection/prevention control ↗
- ·Vulnerability is exclusively limited to 32-bit Redis (running on a 32-bit system or as a 32-bit executable on a 64-bit system); 64-bit Redis deployments are not affected ↗
- ·Only Redis version 4.0 or newer is affected; older versions do not implement the configurable proto-max-bulk-len limit ↗
- ·The default proto-max-bulk-len value of 512MB is safe; the vulnerability is only triggerable if an authenticated user has raised this limit significantly above the default ↗
- ·Red Hat Enterprise Linux 8, Red Hat Software Collections, Red Hat Ansible Automation Platform, Red Hat Ansible Tower, and Red Hat OpenStack Platform are confirmed not affected as they do not ship 32-bit Redis ↗
CVSS provenance
nvdv3.18.8HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
nvdv2.06.5MEDIUMAV:N/AC:L/Au:S/C:P/I:P/A:P
osv8.8HIGH
vendor_msrc8.8HIGH
vendor_debian5.4MEDIUM
vendor_redhat5.4MEDIUM
vendor_ubuntu5.4MEDIUM
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Ubuntu
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Red Hat
redis: integer overflow when configurable limit for maximum supported bulk input size is too big on 32-bit platforms
vendor_redhat·2021-02-22·CVSS 5.4
CVE-2021-21309 [MEDIUM] CWE-190 redis: integer overflow when configurable limit for maximum supported bulk input size is too big on 32-bit platforms
redis: integer overflow when configurable limit for maximum supported bulk input size is too big on 32-bit platforms
Redis is an open-source, in-memory database that persists on disk. In affected versions of Redis an integer overflow bug in 32-bit Redis version 4.0 or newer could be exploited to corrupt the heap and potentially result with remote code execution. Redis 4.0 or newer uses a configurable limit for the maximum supported bulk input size. By default, it is 512MB which is a safe value for all platforms. If the limit is significantly increased, receiving a large request from a client may trigger several integer overflow scenarios, which would result with buffer overflow and heap corruption. We believe this could in certain conditions be exploited for remote code execution. By defa
Microsoft
Integer overflow on 32-bit systems
vendor_msrc·2021-02-09·CVSS 8.8
CVE-2021-21309 [MEDIUM] CWE-190 Integer overflow on 32-bit systems
Integer overflow on 32-bit systems
FAQ: Is Azure Linux the only Microsoft product that includes this open-source library and is therefore potentially affected by this vulnerability?
One of the main benefits to our customers who choose to use the Azure Linux distro is the commitment to keep it up to date with the most recent and most secure versions of the open source libraries with which the distro is composed. Microsoft is committed to transparency in this work which is why we began publishing CSAF/VEX in October 2025. See this blog post for more information. If impact to additional products is identified, we will update the CVE to reflect this.
Mariner: Mariner
GitHub_M: GitHub_M
Customer Action Required: Yes
Remediation: CBL-Mariner Releases
Reference: https://learn.microsoft.com/
Debian
CVE-2021-21309: redis - Redis is an open-source, in-memory database that persists on disk. In affected v...
vendor_debian·2021·CVSS 5.4
CVE-2021-21309 [MEDIUM] CVE-2021-21309: redis - Redis is an open-source, in-memory database that persists on disk. In affected v...
Redis is an open-source, in-memory database that persists on disk. In affected versions of Redis an integer overflow bug in 32-bit Redis version 4.0 or newer could be exploited to corrupt the heap and potentially result with remote code execution. Redis 4.0 or newer uses a configurable limit for the maximum supported bulk input size. By default, it is 512MB which is a safe value for all platforms. If the limit is significantly increased, receiving a large request from a client may trigger several integer overflow scenarios, which would result with buffer overflow and heap corruption. We believe this could in certain conditions be exploited for remote code execution. By default, authenticated Redis users have access to all configuration parameters and can therefore use the “CONFIG SET proto
OSV
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osv·2022-08-03·CVSS 8.8
CVE-2021-32626 [HIGH] redis vulnerabilities
redis vulnerabilities
It was discovered that Redis incorrectly handled certain specially crafted
Lua scripts. A remote attacker could possibly use this issue to cause a
denial of service or execute arbitrary code. (CVE-2021-32626)
It was discovered that Redis incorrectly handled some malformed requests
when using Redis Lua Debugger. A remote attacker could possibly use this
issue to cause a denial of service or other unspecified impact. This issue
only affected Ubuntu 18.04 ESM and Ubuntu 20.04 ESM. (CVE-2021-32672)
It was discovered that Redis incorrectly handled certain Redis Standard
Protocol (RESP) requests. A remote attacker could possibly use this issue
to cause a denial of service. (CVE-2021-32675)
It was discovered that Redis incorrectly handled some configuration
parameters wi
OSV
CVE-2021-21309: Redis is an open-source, in-memory database that persists on disk
osv·2021-02-26·CVSS 8.8
CVE-2021-21309 [HIGH] CVE-2021-21309: Redis is an open-source, in-memory database that persists on disk
Redis is an open-source, in-memory database that persists on disk. In affected versions of Redis an integer overflow bug in 32-bit Redis version 4.0 or newer could be exploited to corrupt the heap and potentially result with remote code execution. Redis 4.0 or newer uses a configurable limit for the maximum supported bulk input size. By default, it is 512MB which is a safe value for all platforms. If the limit is significantly increased, receiving a large request from a client may trigger several integer overflow scenarios, which would result with buffer overflow and heap corruption. We believe this could in certain conditions be exploited for remote code execution. By default, authenticated Redis users have access to all configuration parameters and can therefore use the “CONFIG SET proto
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
https://github.com/redis/redis/commit/c992857618db99776917f10bf4f2345a5fdc78b0https://github.com/redis/redis/pull/8522https://github.com/redis/redis/security/advisories/GHSA-hgj8-vff2-7cjfhttps://security.gentoo.org/glsa/202103-02https://github.com/redis/redis/commit/c992857618db99776917f10bf4f2345a5fdc78b0https://github.com/redis/redis/pull/8522https://github.com/redis/redis/security/advisories/GHSA-hgj8-vff2-7cjfhttps://security.gentoo.org/glsa/202103-02
2021-02-26
Published