CVE-2021-3621

HIGHNVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2021-12-24. NVD baseline CVSS 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
8.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 3%CVSS: 8.8Exploit: None knownExposed: 0

A fix is available — apply it.

A flaw was found in SSSD, where the sssctl command was vulnerable to shell command injection via the logs-fetch and cache-expire subcommands. This flaw allows an attacker to trick the root user into running a specially crafted sssctl command, such as via sudo, to gain root access. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.

CVSS v3
8.8
EG Score
8.8(medium)
EG Risk
45(Track)
EG Risk 45/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity88% × 45%
Exploitation3% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
3%
EPSS %ILE
83%
KEV
Not listed

Published

December 23, 2021

Last Modified

November 3, 2025

References (7)

Vendor Advisories for CVE-2021-3621(6)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(7)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntusssd-proxy (2.4.0-1ubuntu6.1) @ hirsute2026-05-26ubuntu
redhatredhat-virtualization-host-0:4.3.18-20210903.0.el7_92021-09-09redhat
redhatsssd-0:1.16.5-10.el7_9.102021-08-31redhat
redhatsssd-0:2.2.3-20.el8_2.12021-08-31redhat
redhatredhat-virtualization-host-0:4.4.7-20210804.0.el8_42021-08-19redhat
redhatsssd-0:2.2.0-19.el8_1.22021-08-17redhat
redhatsssd-0:2.4.0-9.el8_4.22021-08-16redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 10× in last 7d / 48× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 113 total refreshes for this CVE.

  1. 2026-07-26 14:52 UTCEPSS rescore
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Frequently asked(5)

What is CVE-2021-3621?
CVE-2021-3621 is a high vulnerability published on December 23, 2021. A flaw was found in SSSD, where the sssctl command was vulnerable to shell command injection via the logs-fetch and cache-expire subcommands. This flaw allows an attacker to trick the root user into running a specially crafted sssctl command, such as via sudo, to gain root access. The highest…
When was CVE-2021-3621 disclosed?
CVE-2021-3621 was first published in the National Vulnerability Database on December 23, 2021, with the most recent update on November 3, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-3621 actively exploited?
CVE-2021-3621 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 3% probability of exploitation in the next 30 days, which ranks it in the top 16.8% of all scored CVEs.
What is the CVSS score of CVE-2021-3621?
CVE-2021-3621 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2021-3621?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-3621, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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