CVE-2021-23727 | Stored Command Injection

Exp

This affects the package celery before 5.2.2. It by default trusts the messages and metadata stored in backends (result stores). When reading task metadata from the backend, the data is deserialized. Given that an attacker can gain access to, or somehow manipulate the metadata within a celery backend, they could trigger a stored command injection vulnerability and potentially gain further access to the system.

Published: 2021-12-29 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-23727 is rated High Exploit Risk (78.6/100): CVSS High severity, with medium exploitation likelihood (EPSS 3.88%). 1 public exploit reference(s) are indexed (Exploit-DB). EPSS rose +2.48% over the last day, indicating growing attacker interest. Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

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

Public exploit references (Exploit-DB) for CVE-2021-23727

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-23727

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 1.40% 3.88% +2.48%
2 2026-04-15 0.65% 1.40% +0.74%
3 2026-04-07 — 0.65% —

Full EPSS history (20 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-23727

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]
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]
6.0 2.0 MEDIUM
AV:N/AC:M/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:M)
Exploitation needs some favorable conditions, but not exceptional ones.
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.
 6.8 6.4 [email protected]

Weakness enumeration for CVE-2021-23727

GitHub Security Advisory for CVE-2021-23727

OS Trackers for CVE-2021-23727

vendor priority summary link
debian not yet assigned CVE-2021-23727 not yet assigned priority: Debian including 1 source packages (celery), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 4, open 1. https://security-tracker.debian.org/tracker/CVE-2021-23727
redhat medium — https://access.redhat.com/security/cve/CVE-2021-23727
ubuntu medium CVE-2021-23727 medium priority: Ubuntu including 1 source packages (celery), 15 status rows across 15 suites (bionic, focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 7, needs-triage 5, ignored 2, released 1. https://ubuntu.com/security/CVE-2021-23727

Affected software / configurations for CVE-2021-23727

Vendor Product Version Raw CPE
celeryproject celery < 5.2.2 cpe:2.3:a:celeryproject:celery:*:*:*:*:*:python:*:*
fedoraproject extra_packages_for_enterprise_linux 7.0 cpe:2.3:a:fedoraproject:extra_packages_for_enterprise_linux:7.0:*:*:*:*:*:*:*
fedoraproject fedora 35 cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*

References for CVE-2021-23727

cvelogic Threat Intelligence