CVE-2021-3470

A heap overflow issue was found in Redis in versions before 5.0.10, before 6.0.9 and before 6.2.0 when using a heap allocator other than jemalloc or glibc's malloc, leading to potential out of bound write or process crash. Effectively this flaw does not affect the vast majority of users, who use jemalloc or glibc malloc.

Published: 2021-03-31 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-3470 is rated Moderate Risk (43.8/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.14%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-3470

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.42% 1.14% +0.72%
2 2026-05-26 0.66% 0.42% -0.24%
3 2025-12-28 — 0.66% —

Full EPSS history (19 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-3470

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 3.9 1.4 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2021-3470

OS Trackers for CVE-2021-3470

vendor priority summary link
alpine medium CVE-2021-3470: 1 source package rows (redis); 21 state rows across 9 repos (3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-community, 3.21-community, 3.22-community, edge-community, edge-main); fixed 9, open 12. https://security.alpinelinux.org/vuln/CVE-2021-3470
debian unimportant CVE-2021-3470 unimportant priority: Debian including 1 source packages (redis), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-3470
redhat low — https://access.redhat.com/security/cve/CVE-2021-3470
suse medium CVE-2021-3470 severity moderate: SUSE including 1 source package names (redis), 1 product×package rows across 1 product lines (SUSE Linux Enterprise Module for Server Applications 15 SP2): Known Not Affected 1. https://www.suse.com/security/cve/CVE-2021-3470/
ubuntu negligible CVE-2021-3470 negligible priority: Ubuntu including 1 source packages (redis), 16 status rows across 16 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 10, needed 4, ignored 1, released 1. https://ubuntu.com/security/CVE-2021-3470

Affected software / configurations for CVE-2021-3470

Vendor Product Version Raw CPE
redislabs redis < 5.0.10 cpe:2.3:a:redislabs:redis:*:*:*:*:*:*:*:*
redislabs redis >= 6.0.0, < 6.0.9 cpe:2.3:a:redislabs:redis:*:*:*:*:*:*:*:*
redislabs redis 6.2.0 cpe:2.3:a:redislabs:redis:6.2.0:rc1:*:*:*:*:*:*
redislabs redis 6.2.0 cpe:2.3:a:redislabs:redis:6.2.0:rc2:*:*:*:*:*:*
redislabs redis 6.2.0 cpe:2.3:a:redislabs:redis:6.2.0:rc3:*:*:*:*:*:*

References for CVE-2021-3470

URL Tags
https://bugzilla.redhat.com/show_bug.cgi?id=1943623 Issue Tracking Patch Third Party Advisory
cvelogic Threat Intelligence