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CVE-2021-32628· NVD / CVE Program· CNA GitHub_M

Vulnerability in handling large ziplists

Redis is an open source, in-memory database that persists on disk. An integer overflow bug in the ziplist data structure used by all versions of Redis can be exploited to corrupt the heap and potentially result with remote code execution. The vulnerability involves modifying the default ziplist configuration parameters (hash-max-ziplist-entries, hash-max-ziplist-value, zset-max-ziplist-entries or zset-max-ziplist-value) to a very large value, and then constructing specially crafted commands to create very large ziplists. The problem is fixed in Redis versions 6.2.6, 6.0.16, 5.0.14. An additional workaround to mitigate the problem without patching the redis-server executable is to prevent users from modifying the above configuration parameters. This can be done using ACL to restrict unprivileged users from using the CONFIG SET command.

HighCVSS 7.5 · v3.1—No exploit Fix available

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Published
Oct 4, 2021
Updated
Jun 16, 2026
EPSS
13.5% · 96th percentile
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Report tools

JSON

Action score

34

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
4 / 30 · 13.5%

CNA vs NVD score

NVD
7.5
CNA · GitHub_M
7.5
agree

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

Affected systems

VendorProduct
redisredis
fedoraprojectfedora
debiandebian linux
netappmanagement services for element software
netappmanagement services for netapp hci
oraclecommunications operations monitor

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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 redis5.0.0 and later · before 5.0.14
  • redis redis6.0.0 and later · before 6.0.16
  • redis redis6.2.0 and later · before 6.2.6

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

    • >= 6.2.0, < 6.2.6, >= 6.0.0, < 6.0.16, < 5.0.14affected

Package-level exposure

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

EcosystemPackageAffected rangeFix
AlmaLinux:8redisbefore 5.0.3-5.module_el8.4.0+2583+b98453225.0.3-5.module_el8.4.0+2583+b9845322
AlmaLinux:8redisbefore 6.0.9-5.module_el8.4.0+2584+1bb0d2aa6.0.9-5.module_el8.4.0+2584+1bb0d2aa
AlmaLinux:8redisbefore 6.0.9-5.module_el8.5.0+67+a3c431d96.0.9-5.module_el8.5.0+67+a3c431d9
AlmaLinux:8redisbefore 5.0.3-5.module_el8.5.0+66+fc19ec125.0.3-5.module_el8.5.0+66+fc19ec12
AlmaLinux:8redis-develbefore 5.0.3-5.module_el8.5.0+66+fc19ec125.0.3-5.module_el8.5.0+66+fc19ec12
AlmaLinux:8redis-develbefore 6.0.9-5.module_el8.4.0+2584+1bb0d2aa6.0.9-5.module_el8.4.0+2584+1bb0d2aa
AlmaLinux:8redis-develbefore 6.0.9-5.module_el8.5.0+67+a3c431d96.0.9-5.module_el8.5.0+67+a3c431d9
AlmaLinux:8redis-develbefore 5.0.3-5.module_el8.4.0+2583+b98453225.0.3-5.module_el8.4.0+2583+b9845322
AlmaLinux:8redis-docbefore 5.0.3-5.module_el8.4.0+2583+b98453225.0.3-5.module_el8.4.0+2583+b9845322
AlmaLinux:8redis-docbefore 6.0.9-5.module_el8.4.0+2584+1bb0d2aa6.0.9-5.module_el8.4.0+2584+1bb0d2aa
Alpine:v3.11redisfrom 5.0.0 · before 5.0.14-r05.0.14-r0
Alpine:v3.13redisfrom 5.0.0 · before 6.0.16-r06.0.16-r0
Alpine:v3.14redisfrom 5.0.0 · before 6.2.6-r06.2.6-r0
Debian:10redisbefore 5:5.0.14-1+deb10u15:5.0.14-1+deb10u1
Debian:11redisbefore 5:6.0.16-1+deb11u15:6.0.16-1+deb11u1
Debian:12redisbefore 5:6.0.16-15:6.0.16-1
openSUSE:Leap 15.3redisbefore 6.0.14-6.8.16.0.14-6.8.1
openSUSE:Tumbleweedredisbefore 6.2.6-1.16.2.6-1.1
Red Hat:enterprise_linux:8::appstreamredisbefore 0:6.0.9-5.module+el8.4.0+12929+1bb0d2aa0:6.0.9-5.module+el8.4.0+12929+1bb0d2aa
Red Hat:enterprise_linux:8::appstreamredisbefore 0:5.0.3-5.module+el8.4.0+12927+b98453220:5.0.3-5.module+el8.4.0+12927+b9845322
Red Hat:enterprise_linux:8::appstreamredis-debuginfobefore 0:6.0.9-5.module+el8.4.0+12929+1bb0d2aa0:6.0.9-5.module+el8.4.0+12929+1bb0d2aa
Red Hat:enterprise_linux:8::appstreamredis-debuginfobefore 0:5.0.3-5.module+el8.4.0+12927+b98453220:5.0.3-5.module+el8.4.0+12927+b9845322
Red Hat:enterprise_linux:8::appstreamredis-debugsourcebefore 0:6.0.9-5.module+el8.4.0+12929+1bb0d2aa0:6.0.9-5.module+el8.4.0+12929+1bb0d2aa
Red Hat:enterprise_linux:8::appstreamredis-debugsourcebefore 0:5.0.3-5.module+el8.4.0+12927+b98453220:5.0.3-5.module+el8.4.0+12927+b9845322

+23

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
  • CVE-2022-24834Heap overflow issue with the Lua cjson library used by Redis
    47Plan
  • CVE-2023-22458Integer overflow in multiple Redis commands can lead to denial-of-service
    44Plan
  • CVE-2024-46981Redis' Lua library commands may lead to remote code execution
    41Plan

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
almalinux:redis5.0.3-5.module_el8.4.0+2583+b9845322 · AlmaLinux:8Package registry (OSV)
almalinux:redis-devel5.0.3-5.module_el8.5.0+66+fc19ec12 · AlmaLinux:8Package registry (OSV)
almalinux:redis-doc5.0.3-5.module_el8.4.0+2583+b9845322 · AlmaLinux:8Package registry (OSV)
alpine:redis5.0.14-r0 · Alpine:v3.11Package registry (OSV)
debian:redis5:6.0.16-1 · Debian:12Package registry (OSV)
opensuse:redis6.0.14-6.8.1 · openSUSE:Leap 15.3Package registry (OSV)
red hat:redis0:5.0.3-5.module+el8.4.0+12927+b9845322 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:redis-debuginfo0:5.0.3-5.module+el8.4.0+12927+b9845322 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:redis-debugsource0:5.0.3-5.module+el8.4.0+12927+b9845322 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:redis-devel0:5.0.3-5.module+el8.4.0+12927+b9845322 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:redis-doc0:5.0.3-5.module+el8.4.0+12927+b9845322 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:rh-redis5-redis0:5.0.5-3.el7 · Red Hat:rhel_software_collections:3::el7Package registry (OSV)
red hat:rh-redis5-redis-debuginfo0:5.0.5-3.el7 · Red Hat:rhel_software_collections:3::el7Package registry (OSV)
rocky linux:redis0:5.0.3-5.module+el8.5.0+657+2674830e · Rocky Linux:8Package registry (OSV)
suse:redis6.0.14-6.8.1 · SUSE:Linux Enterprise Module for Server Applications 15 SP2Package registry (OSV)

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.

EPSS, last 120 days+1% in 7 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

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

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.

No nightly-computed relations.

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.
  • A low-privileged account is enough.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

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

CVSS vector

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

nvd-primary

Attack context

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

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

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

References

All records