CVE-2025-21605VulnerabilityPublished 12 May 2025Updated 30 Oct 2026

Red Hat Security Advisory: redis security update

Affects Red Hat redisSource GCVE Database

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Not known to be exploited.

Data as of 30 Oct 2026, 22:06 UTC

Severity

High

Rated by Threat Radar · No CVSS score from NVD or the CNA

EPSS: 0.8% chance of exploitation in 30 days – higher than 58% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

Exploitation evidence

Disclosed: evidence found.
CVE published 12 May 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 30 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

AI-suggested

Red Hat has released updated Redis packages (version 6.2.7-1.el9_4.2) for Red Hat Enterprise Linux 9.4 Extended Update Support and related variants that fix this vulnerability. Users should apply these official updates promptly to remediate the issue. Refer to Red Hat's official advisory and update instructions at https://access.redhat.com/articles/11258. No additional mitigation steps are indicated or required beyond applying the update.

Description

A denial of service (DoS) vulnerability (CVE-2025-21605) has been identified in Redis, a popular in-memory key-value store. The flaw allows an unauthenticated client to abuse unlimited growth of output buffers, potentially causing service disruption. Red Hat has issued a security update addressing this issue for multiple Red Hat Enterprise Linux 9.4 variants. The vulnerability is rated as having a high security impact. No public exploit code or in-the-wild exploitation has been reported. Users of affected Red Hat Enterprise Linux 9.4 versions should apply the provided update to mitigate the risk.

Impact

The vulnerability allows unauthenticated clients to cause a denial of service by triggering unlimited growth of Redis output buffers, potentially exhausting system resources and disrupting service availability. This can affect any Redis deployment using the affected versions on Red Hat Enterprise Linux 9.4 variants. There is no indication of privilege escalation or data compromise from the provided information.

Summary

CVE-2025-21605 is a denial of service vulnerability in Redis caused by unlimited growth of output buffers that can be abused by unauthenticated clients. This flaw can lead to resource exhaustion and service disruption. Red Hat has released a security update for Redis version 6.2.7-1.el9_4.2 in Red Hat Enterprise Linux 9.4 Extended Update Support and related variants. The advisory rates the impact as important/high and provides updated packages to remediate the issue. No CVSS score is provided in the advisory, and no known exploits are reported in the wild.

CWE-770Allocation of Resources Without Limits or Throttling (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #25
The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.
Requirements
Clearly specify the minimum and maximum expectations for capabilities, and dictate which behaviors are acceptable when resource allocation reaches limits.
Architecture and Design
Limit the amount of resources that are accessible to unprivileged users. Set per-user limits for resources. Allow the system administrator to define these limits. Be careful to avoid CWE-410.
Architecture and Design
Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended.
OWASP Cheat Sheets
Abuse Case (opens in a new tab)
OWASP ASVS 4.0.3
V8.1.4 (opens in a new tab)
V13.4.1 (opens in a new tab)
V11.1.4 (opens in a new tab)
Attack patterns
XML Ping of the Death (opens in a new tab)
Exponential Data Expansion (opens in a new tab)
Serialized Data Parameter Blowup (opens in a new tab)
Serialized Data with Nested Payloads (opens in a new tab)
Oversized Serialized Data Payloads (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 30 Oct 2026, 22:06 UTC

WeaknessesCWE-770

Technical details

References

Community reviews

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