Is CVE-2021-22538 in the CISA KEV catalog?

No. CVE-2021-22538 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-22538?

CVE-2021-22538 has a CVSS v3 base score of 6.3 (MEDIUM).

What is the EPSS score for CVE-2021-22538?

CVE-2021-22538 has an EPSS score of 0.72% (49th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-22538?

Upgrade exposure notifications verification server to 0.23.1 or later.

CVE & CISA-KEV Catalog

CVE-2021-22538

MEDIUM

6.3

CVSS v3

NVD

Description

A privilege escalation vulnerability impacting the Google Exposure Notification Verification Server (versions prior to 0.23.1), allows an attacker who (1) has UserWrite permissions and (2) is using a carefully crafted request or malicious proxy, to create another user with higher privileges than their own. This occurs due to insufficient checks on the allowed set of permissions. The new user creation event would be captured in the Event Log.

CWE-20Improper Input Validation CWE-276

How to fix

Remediation Available

exposure notifications verification serverNVD

Affected:< 0.23.1Fixed in:0.23.1CVE-2021-22538derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityLow

IntegrityLow

AvailabilityLow

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

Exploit Intelligence

0.72%probability of exploitation in 30 days

49thpercentile

Moderate risk: more likely to be exploited than 49% of all known CVEs.

References

Patch1

github.com

Third-Party Advisory3

Related Vulnerabilities

Other CWE-20 (Improper Input Validation) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2024-3400	Critical	10.0	100%	KEV + Ransom	-
CVE-2021-45105	Medium	5.9	100%	-	Fix
CVE-2021-44228	Critical	10.0	100%	KEV + Ransom	Fix
CVE-2021-21985	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2018-7600	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2020-3452	High	7.5	100%	KEV	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.