What is the CVSS score of CVE-2025-21605?

CVE-2025-21605 has a CVSS 3.1 base score of 7.5 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. EPSS exploitation probability: 0.4%.

How to fix or mitigate CVE-2025-21605?

Within 7 days: Identify all affected systems running versions starting at 2.6 and and apply vendor patches promptly. Monitor vendor channels for patch availability.

Redis CVE-2025-21605

HIGH

Allocation of Resources Without Limits or Throttling (CWE-770)

2025-04-23 security-advisories@github.com

Denial Of Service Redis Debian Red Hat Debian Linux Valkey Suse Lfprojects

7.5

CVSS 3.1 · GitHub Advisory

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Vulnerability Assessment

Weakness	CWE CWE-770 OWASP Top 10:2025 A06:2025 - Insecure Design ASVS 5.0 V2 - Validation and Business Logic Resource allocation limits MITRE ATT&CK 1 technique across 1 tactic: Impact The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Impact	CVSS score of 7.5 (HIGH). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. EPSS exploitation probability: 0.36%.
Exploit ScenarioDerived	A remote attacker could exhaust system resources through uncontrolled allocation by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).

Patch available 0.4% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 28, 2026

Redis is an open source, in-memory database that persists on disk. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Set resource limits, implement rate limiting, validate input sizes.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Allocation of Resources Without Limits (CWE-770), which allows attackers to exhaust system resources through uncontrolled allocation. Redis is an open source, in-memory database that persists on disk. In versions starting at 2.6 and prior to 7.4.3, An unauthenticated client can cause unlimited growth of output buffers, until the server runs out of memory or is killed. By default, the Redis configuration does not limit the output buffer of normal clients (see client-output-buffer-limit). Therefore, the output buffer can grow unlimitedly over time. As a result, the service is exhausted and the memory is unavailable. When password authentication is enabled on the Redis server, but no password is provided, the client can still cause the output buffer to grow from "NOAUTH" responses until the system will run out of memory. This issue has been patched in version 7.4.3. An additional workaround to mitigate this problem without patching the redis-server executable is to block access to prevent unauthenticated users from connecting to Redis. This can be done in different ways. Either using network access control tools like firewalls, iptables, security groups, etc, or enabling TLS and requiring users to authenticate using client side certificates. Affected products include: Redis, Lfprojects Valkey, Debian Debian Linux. Version information: prior to 7.4.3.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

GitHub Advisory PRIMARY 7.5 HIGH

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

SUSE HIGH

Red Hat 7.5 HIGH

Primary rating from GitHub Advisory.

CVSS VectorGitHub Advisory

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Lifecycle Timeline

Patch released

Apr 05, 2026 - 08:30 nvd

Patch available

CVE Published

Apr 23, 2025 - 16:15 nvd

HIGH 7.5

DescriptionGitHub Advisory

Redis is an open source, in-memory database that persists on disk. In versions starting at 2.6 and prior to 7.4.3, An unauthenticated client can cause unlimited growth of output buffers, until the server runs out of memory or is killed. By default, the Redis configuration does not limit the output buffer of normal clients (see client-output-buffer-limit). Therefore, the output buffer can grow unlimitedly over time. As a result, the service is exhausted and the memory is unavailable. When password authentication is enabled on the Redis server, but no password is provided, the client can still cause the output buffer to grow from "NOAUTH" responses until the system will run out of memory. This issue has been patched in version 7.4.3. An additional workaround to mitigate this problem without patching the redis-server executable is to block access to prevent unauthenticated users from connecting to Redis. This can be done in different ways. Either using network access control tools like firewalls, iptables, security groups, etc, or enabling TLS and requiring users to authenticate using client side certificates.

Executive ViewAI

Why It Matters

Organizations using versions starting at 2.6 and face notable risk from CVE-2025-21605 rated CVSS 7.5. Exploitation could compromise the security of affected deployments. Organizations should apply vendor updates when available and consider compensating controls in the interim.

Business Impact: High

Compensating Controls

Apply vendor patch. If immediate patching is not feasible: (1) Implement network-level access controls to limit exposure; (2) Enable enhanced monitoring and alerting; (3) Apply principle of least privilege.

Threat Intelligence Overview

EPSS Score

0.4%

Top 42% exploitable

Data Quality

4 sources

Confidence: Medium

NVD

CVE.org

EPSS Vendor

GitHub

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity HIGH

CISA KEV No

Public POC No

EPSS 0.4%

Patch available Yes

Active threat No

Deciding rule

HIGH severity (CVSS 7.0-8.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Scheduled

Exploitation· derived

None

System Exposure· derived

Open

Automatable· derived

Yes

Human Impact

High

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +38

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Denial of Service MEDIUM

Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.

Affected Products (CPE)GitHub Advisory

cpe:2.3:a:redis:redis:*:*:*:*:*:*:*:*

cpe:2.3:a:lfprojects:valkey:*:*:*:*:*:*:*:*

cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

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Vendor StatusVendor

SUSE

Severity: High

Product	Status
Container private-registry/harbor-valkey:8.0.2-2.17 Container suse/valkey:8.0.2-8.1 Image pr_15_6	Affected
SUSE Enterprise Storage 7.1	Fixed
SUSE Liberty Linux 8	Fixed
SUSE Liberty Linux 9	Fixed
SUSE Linux Enterprise High Performance Computing 15 SP3-LTSS	Fixed

References

Advisories & patches

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