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NVD / CVE Program· CNA GitHub_M

CVE-2025-21605: Redis DoS Vulnerability due to unlimited growth of output buffers abused by unauthenticated client

Noroxi assessment

Priority: Monitor (action score 30/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.87% (FIRST EPSS); higher than 59.1% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: redis redis 7.4.3; azl3 valkey 8.0.2-1 on Azure Linux 3.0 8.0.3-1; azl3 valkey 8.0.3-1 on Azure Linux 3.0 8.0.3-1.

Low priority for now. Upgrade to redis redis 7.4.3; azl3 valkey 8.0.2-1 on Azure Linux 3.0 8.0.3-1; azl3 valkey 8.0.3-1 on Azure Linux 3.0 8.0.3-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 7.5 · v3.1—No exploit Fix available
Published
Apr 23, 2025
Updated
Jun 17, 2026
EPSS
0.8% · 59th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.8%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
7.5
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • Not in KEV: no record of exploitation in the wild
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  • A fix has been released

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
redisredis
lfprojectsvalkey
debiandebian linux

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When you'll hear from us

  • when a new CVE affecting this product is published
  • when a record in your stack enters KEV or gets exploit code

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Running WordPress? Scan your site free with WP Lens

  • Stack alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
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  • 10 scans an hour on the security tools (3 a day without an account), an API key and MCP
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All free tools

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Free account, no card. Unfollow any time.

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Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • redis redis2.6.0 and later · before 6.2.18
  • redis redis7.0 and later · before 7.2.8
  • redis redis7.4.0 and later · before 7.4.3

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • redis redis

    • >= 2.6, < 7.4.3affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:10valkeybefore 8.0.3-1.el10_08.0.3-1.el10_0
AlmaLinux:10valkey-develbefore 8.0.3-1.el10_08.0.3-1.el10_0
AlmaLinux:8redisbefore 6.2.18-1.module_el8.10.0+3994+c2cc53956.2.18-1.module_el8.10.0+3994+c2cc5395
AlmaLinux:8redis-develbefore 6.2.18-1.module_el8.10.0+3994+c2cc53956.2.18-1.module_el8.10.0+3994+c2cc5395
AlmaLinux:8redis-docbefore 6.2.18-1.module_el8.10.0+3994+c2cc53956.2.18-1.module_el8.10.0+3994+c2cc5395
AlmaLinux:9redisbefore 7.2.8-1.module_el9.6.0+168+b8d8e9007.2.8-1.module_el9.6.0+168+b8d8e900
AlmaLinux:9redisbefore 6.2.18-1.el9_66.2.18-1.el9_6
AlmaLinux:9redis-develbefore 6.2.18-1.el9_66.2.18-1.el9_6
AlmaLinux:9redis-develbefore 7.2.8-1.module_el9.6.0+168+b8d8e9007.2.8-1.module_el9.6.0+168+b8d8e900
AlmaLinux:9redis-docbefore 6.2.18-1.el9_66.2.18-1.el9_6
AlmaLinux:9redis-docbefore 7.2.8-1.module_el9.6.0+168+b8d8e9007.2.8-1.module_el9.6.0+168+b8d8e900
Alpine:v3.15redisfrom 2.6.0 · before 6.2.18-r06.2.18-r0
Alpine:v3.18redisfrom 2.6.0 · before 7.0.15-r37.0.15-r3
Alpine:v3.19redisfrom 2.6.0 · before 7.2.8-r07.2.8-r0
Alpine:v3.20redictbefore 7.3.3-r07.3.3-r0
Alpine:v3.20valkeyfrom 7.2.4 · before 7.2.9-r07.2.9-r0
Alpine:v3.22redisfrom 2.6.0 · before 8.0.0-r08.0.0-r0
Debian:11redisbefore 5:6.0.16-1+deb11u65:6.0.16-1+deb11u6
Debian:12redisbefore 5:7.0.15-1~deb12u45:7.0.15-1~deb12u4
Debian:13redisbefore 5:7.0.15-3.15:7.0.15-3.1
Debian:13valkeybefore 8.1.1+dfsg1-18.1.1+dfsg1-1
Debian:14redictbefore 7.3.5+ds-17.3.5+ds-1
openSUSE:Leap 15.6redisbefore 7.2.4-150600.3.9.17.2.4-150600.3.9.1
openSUSE:Leap 15.6redis7before 7.0.8-150600.8.9.17.0.8-150600.8.9.1

+72

Same product

redis: all records

Other highest-scoring records for the same primary product.

  • CVE-2022-0543It was discovered, that redis, a persistent key-value database, due to a packaging issue, is prone to a (Debian-specific) Lua sandbox escapeKEV
    100Now
  • CVE-2025-49844Redis Lua Use-After-Free may lead to remote code execution
    64This week
  • CVE-2023-36824Heap overflow in COMMAND GETKEYS and ACL evaluation in Redis
    58Plan

Published before and after this one in the same product

  • ← EarlierCVE-2024-46981Jan 6, 2025 · Redis' Lua library commands may lead to remote code execution
    41Plan
  • ← EarlierCVE-2024-51741Jan 6, 2025 · Redis allows denial-of-service due to malformed ACL selectors
    17Monitor
  • Later →CVE-2025-27151May 29, 2025 · redis-check-aof may lead to stack overflow and potential RCE
    39Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
redis redis7.4.3 · descriptionVendor (CNA)
azl3 valkey 8.0.2-1 on Azure Linux 3.08.0.3-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 valkey 8.0.3-1 on Azure Linux 3.08.0.3-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
almalinux:redis7.2.8-1.module_el9.6.0+168+b8d8e900 · AlmaLinux:9Package registry (OSV)
almalinux:redis-devel7.2.8-1.module_el9.6.0+168+b8d8e900 · AlmaLinux:9Package registry (OSV)
almalinux:redis-doc7.2.8-1.module_el9.6.0+168+b8d8e900 · AlmaLinux:9Package registry (OSV)
almalinux:valkey8.0.3-1.el10_0 · AlmaLinux:10Package registry (OSV)
almalinux:valkey-devel8.0.3-1.el10_0 · AlmaLinux:10Package registry (OSV)
alpine:redict7.3.3-r0 · Alpine:v3.20Package registry (OSV)
alpine:redis6.2.18-r0 · Alpine:v3.15Package registry (OSV)
alpine:valkey7.2.9-r0 · Alpine:v3.20Package registry (OSV)
debian:redict7.3.5+ds-1 · Debian:14Package registry (OSV)
debian:redis5:7.0.15-1~deb12u4 · Debian:12Package registry (OSV)
debian:valkey8.1.1+dfsg1-1 · Debian:13Package registry (OSV)
opensuse:redis7.2.4-150600.3.9.1 · openSUSE:Leap 15.6Package registry (OSV)
opensuse:redis77.0.8-150600.8.9.1 · openSUSE:Leap 15.6Package registry (OSV)
opensuse:valkey8.0.2-150600.13.6.1 · openSUSE:Leap 15.6Package registry (OSV)
red hat:discovery-cli0:1.14.0-1.el8 · Red Hat:discovery:1.0::el8Package registry (OSV)
red hat:discovery-installer0:1.14.1-1.el8 · Red Hat:discovery:1.0::el8Package registry (OSV)
red hat:redis0:6.0.9-5.module+el8.4.0+23067+0d16e377.2 · Red Hat:rhel_aus:8.4::appstreamPackage registry (OSV)
red hat:redis-debuginfo0:6.0.9-5.module+el8.4.0+23067+0d16e377.2 · Red Hat:rhel_aus:8.4::appstreamPackage registry (OSV)
red hat:redis-debugsource0:6.0.9-5.module+el8.4.0+23067+0d16e377.2 · Red Hat:rhel_aus:8.4::appstreamPackage registry (OSV)
red hat:redis-devel0:6.0.9-5.module+el8.4.0+23067+0d16e377.2 · Red Hat:rhel_aus:8.4::appstreamPackage registry (OSV)
red hat:redis-doc0:6.0.9-5.module+el8.4.0+23067+0d16e377.2 · Red Hat:rhel_aus:8.4::appstreamPackage registry (OSV)
red hat:valkey0:8.0.3-1.el10_0 · Red Hat:enterprise_linux:10.0Package registry (OSV)
red hat:valkey-debuginfo0:8.0.3-1.el10_0 · Red Hat:enterprise_linux:10.0Package registry (OSV)
red hat:valkey-debugsource0:8.0.3-1.el10_0 · Red Hat:enterprise_linux:10.0Package registry (OSV)
red hat:valkey-devel0:8.0.3-1.el10_0 · Red Hat:enterprise_linux:10.0Package registry (OSV)
rocky linux:redis0:7.2.8-1.module+el9.6.0+32036+eb8f79e6 · Rocky Linux:9Package registry (OSV)
rocky linux:valkey0:8.0.3-1.el10_0 · Rocky Linux:10Package registry (OSV)

+6

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2025-4836775 days apartRedis DoS Vulnerability due to bad connection error handling
    30Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-770 · Allocation of Resources Without Limits or Throttling

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (5 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records