Vulnerability in redis (ALPINE-CVE-2021-21309)
Summary
Vulnerability in redis (ALPINE-CVE-2021-21309). Successful exploitation can lead to full system takeover. Mitigation: upgrade to 5.0.11-r0 or later.
Original description
The description as published by the source.
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 stri…
Source: OSV.dev (Open Source Vulnerabilities) OSV
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as ALPINE-CVE-2021-21309 has been found in redis.
Successful exploitation can lead to full system takeover.
What to do: upgrade redis to 5.0.11-r0 or later.
If unsure, ask your IT team or search "redis ALPINE-CVE-2021-21309" on the vendor's site.
ALPINE-CVE-2021-21309 (redis)
Attack vector: remote (network-reachable) / no user interaction
Patched: 5.0.11-r0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (unclassified) exists in redis.
Check the vendor advisory for the affected versions of redis.
Severity: ?. Successful exploitation can lead to full system takeover.
Update to 5.0.11-r0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'redis' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r 'redis' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
redisを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade redis to 5.0.11-r0ステージング環境で 5.0.11-r0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
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3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory security.alpinelinux.org