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CVE-2021-32762· NVD / CVE Program· CNA GitHub_M

Integer overflow that can lead to heap overflow in redis-cli, redis-sentinel on some platforms

Redis is an open source, in-memory database that persists on disk. The redis-cli command line tool and redis-sentinel service may be vulnerable to integer overflow when parsing specially crafted large multi-bulk network replies. This is a result of a vulnerability in the underlying hiredis library which does not perform an overflow check before calling the calloc() heap allocation function. This issue only impacts systems with heap allocators that do not perform their own overflow checks. Most modern systems do and are therefore not likely to be affected. Furthermore, by default redis-sentinel uses the jemalloc allocator which is also not vulnerable. The problem is fixed in Redis versions 6.2.6, 6.0.16 and 5.0.14.

HighCVSS 8.8 · v3.1—No exploit Fix available
Published
Oct 4, 2021
Updated
Jun 16, 2026
EPSS
2.7% · 85th percentile
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Report tools

JSON

Action score

36

Monitor

Low priority for now.

CVSS
35 / 40 · 8.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 2.7%

CNA vs NVD score

NVD
8.8
CNA · GitHub_M
7.5
1.3 point gap

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

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

Affected systems

VendorProduct
redisredis
debiandebian linux
fedoraprojectfedora
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

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

Package-level exposure

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

EcosystemPackageAffected rangeFix
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
Debian:9redisbefore 3:3.2.6-3+deb9u83:3.2.6-3+deb9u8
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
SUSE:Linux Enterprise Module for Server Applications 15 SP2redisbefore 6.0.14-6.8.16.0.14-6.8.1

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
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)
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

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.
  • No special conditions are required; it is repeatable.

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
Low
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:L/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

—

Noroxi analysis

No Noroxi analysis for this record yet

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Change log

  1. Fix✗ → ✓

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References

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