Is CVE-2021-46853 in the CISA KEV catalog?

No. CVE-2021-46853 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-46853?

CVE-2021-46853 has a CVSS v3 base score of 5.9 (MEDIUM).

What is the EPSS score for CVE-2021-46853?

CVE-2021-46853 has an EPSS score of 0.84% (54th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-46853?

Upgrade alpine on debian 12 to 2.25+dfsg1-1 or later. Fixes are available for 4 affected products.

CVE & CISA-KEV Catalog

CVE-2021-46853

MEDIUM

5.9

CVSS v3

NVD

Description

Alpine before 2.25 allows remote attackers to cause a denial of service (application crash) when LIST or LSUB is sent before STARTTLS.

CWE-367TOCTOU Race Condition

How to fix

Remediation Available

alpineDebian

Fixed in:2.25+dfsg1-1CVE-2021-46853

alpineUbuntu

Fixed in:2.20+dfsg1-2ubuntu0.1~esm1USN-7360-1

Fixed in:2.21+dfsg1-1ubuntu0.1~esm1USN-7360-1

Fixed in:2.22+dfsg1-1ubuntu0.1~esm1USN-7360-1

alpine-picoUbuntu

Fixed in:2.20+dfsg1-2ubuntu0.1~esm1USN-7360-1

Fixed in:2.21+dfsg1-1ubuntu0.1~esm1USN-7360-1

Fixed in:2.22+dfsg1-1ubuntu0.1~esm1USN-7360-1

pilotUbuntu

Fixed in:2.20+dfsg1-2ubuntu0.1~esm1USN-7360-1

Fixed in:2.21+dfsg1-1ubuntu0.1~esm1USN-7360-1

Fixed in:2.22+dfsg1-1ubuntu0.1~esm1USN-7360-1

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

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 ComplexityHigh

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

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

Exploit Intelligence

0.84%probability of exploitation in 30 days

54thpercentile

Moderate risk: more likely to be exploited than 54% of all known CVEs.

References

Third-Party Advisory3

Related Vulnerabilities

Other CWE-367 (TOCTOU Race Condition) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2022-36980	High	8.1	83%	-	Fix
CVE-2024-30088	High	7.0	68%	KEV + Ransom	Fix
CVE-2004-0594	Medium	5.1	55%	-	Fix
CVE-2024-50379	Critical	9.8	44%	-	Fix
CVE-2023-38146	High	8.8	39%	-	Fix
CVE-2024-0132	Critical	9.0	37%	-	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 2025-05-05.