CVE-2025-21605: Redis is an open source, in-memory database that persists on disk
Affects redisSource GCVE Database
Not known to be exploited · CVSS 7.5 High : upgrade to 7.2.11+dfsg1-0ubuntu0.2 soon.
Data as of 9 Nov 2026, 14:33 UTC
- Patch
- Available – fixed in 7.2.11+dfsg1-0ubuntu0.2
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 23 Apr 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 9 Nov 2026.
What to do
Upgrade the Ubuntu valkey package to 7.2.11+dfsg1-0ubuntu0.2.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10redictpkg:deb/ubuntu/redict?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 25.10redictpkg:deb/ubuntu/redict?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSredispkg:deb/ubuntu/redis?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSvalkeypkg:deb/ubuntu/valkey?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu Pro 22.04 LTSredispkg:deb/ubuntu/redis?arch=source&distro=esm-apps/jammyOther threats | Affected
| Fixed in– |
Ubuntu Pro 20.04 LTSredispkg:deb/ubuntu/redis?arch=source&distro=esm-apps/focalOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A patch is available in Redis version 7.4.3 that fixes this vulnerability. Users should upgrade to version 7.4.3 or later. If patching is not immediately possible, mitigate by blocking unauthenticated access to Redis using network access controls such as firewalls, iptables, or security groups. Alternatively, enable TLS and require client-side certificate authentication to prevent unauthenticated connections. These mitigations prevent unauthenticated clients from triggering the output buffer growth.
Description
Redis versions starting from 2.6 up to but not including 7.4.3 have a vulnerability where an unauthenticated client can cause unlimited growth of output buffers, leading to memory exhaustion and potential service denial. This occurs because the default configuration does not limit output buffer size for normal clients. Even when password authentication is enabled, unauthenticated clients can trigger buffer growth via repeated "NOAUTH" responses. The issue is fixed in Redis version 7.4.3. Mitigation includes patching to version 7.4.3 or later, or restricting unauthenticated access via network controls or TLS with client certificates.
References
- ubuntu.com/security/CVE-2025-21605 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-21605 (opens in a new tab)
- github.com/redis/redis/security/advisories/GHSA-r67f-p999-2gff (opens in a new tab)
- github.com/valkey-io/valkey/pull/1994 (opens in a new tab)
- github.com/redis/redis/releases/tag/7.4.3 (opens in a new tab)