CVE-2021-29477 | Vulnerability in the STRALGO LCS command

Redis is an open source (BSD licensed), in-memory data structure store, used as a database, cache, and message broker. An integer overflow bug in Redis version 6.0 or newer could be exploited using the `STRALGO LCS` command to corrupt the heap and potentially result with remote code execution. The problem is fixed in version 6.2.3 and 6.0.13. An additional workaround to mitigate the problem without patching the redis-server executable is to use ACL configuration to prevent clients from using the `STRALGO LCS` command.

Published: 2021-05-04 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-29477 is rated Moderate Risk (62.3/100): CVSS High severity, with medium exploitation likelihood (EPSS 4.19%). 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-2021-29477

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 3.30% 4.19% +0.89%
2 2026-06-06 4.32% 3.30% -1.02%
3 2026-06-01 — 4.32% —

Full EPSS history (36 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-29477

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H 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:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
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:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.6 5.9 [email protected]
8.8 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H 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:L)
A normal user session is enough; they don’t have to be admin.
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:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.9 [email protected]
6.5 2.0 MEDIUM
AV:N/AC:L/Au:S/C:P/I:P/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:S)
A single authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.0 6.4 [email protected]

Weakness enumeration for CVE-2021-29477

OS Trackers for CVE-2021-29477

vendor priority summary link
alpine high CVE-2021-29477: 1 source package rows (redis); 8 state rows across 4 repos (3.19-main, 3.22-community, edge-community, edge-main); fixed 0, open 8. https://security.alpinelinux.org/vuln/CVE-2021-29477
debian not yet assigned CVE-2021-29477 not yet assigned 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-2021-29477
gentoo normal CVE-2021-29477: 1 GLSA(s) (202107-20), 1 atom(s) (dev-db/redis); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2021-29477
redhat high — https://access.redhat.com/security/cve/CVE-2021-29477
suse high CVE-2021-29477 severity important: SUSE including 7 source package names (redis-6.0.13-1.10.1, redis-6.0.13-lp152.2.3.1, …), 8 product×package rows across 6 product lines (SUSE Liberty Linux 8, SUSE Linux Enterprise Module for Server Applications 15 SP2, … (6 product lines)): Fixed 8. https://www.suse.com/security/cve/CVE-2021-29477/
ubuntu medium CVE-2021-29477 medium priority: Ubuntu including 1 source packages (redis), 9 status rows across 9 suites (bionic, focal, groovy, hirsute, impish, jammy, trusty, upstream, xenial): not-affected 6, ignored 2, released 1. https://ubuntu.com/security/CVE-2021-29477

Affected software / configurations for CVE-2021-29477

Vendor Product Version Raw CPE
redislabs redis >= 6.0.0, < 6.0.13 cpe:2.3:a:redislabs:redis:*:*:*:*:*:*:*:*
redislabs redis >= 6.2.0, < 6.2.3 cpe:2.3:a:redislabs:redis:*:*:*:*:*:*:*:*
fedoraproject fedora 33 cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
fedoraproject fedora 34 cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*

References for CVE-2021-29477

cvelogic Threat Intelligence