01 Record

CVE-2021-43666

A Denial of Service vulnerability exists in mbed TLS 3.0.0 and earlier in the mbedtls_pkcs12_derivation function when an input password's length is 0.

HighPUBLISHEDCNA: mitre

CNA base score7.5 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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02 Description

A Denial of Service vulnerability exists in mbed TLS 3.0.0 and earlier in the mbedtls_pkcs12_derivation function when an input password's length is 0.

03 Exploitation and scoring

Exploitation

Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.

SSVC decision

ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

2.13% probability of exploitation activity in the next 30 days.

EPSS percentile

Ranks above 80.3% of scored records. A rank, not a probability.

NVD base score

7.5 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

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

NVD analysis status

Modified. NVD last modified this record on 2026-06-17.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published

2022-03-24 00:00Z4 YR AGO

Last updated

2025-12-02 20:51Z9 MO AGO

Reserved

2021-11-15

Assigning CNA

mitre

Record state

PUBLISHED

Severity

High (CVSS 7.5)

CNA CVSS vector

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

Weaknesses

CWE-130Improper Handling of Length Parameter InconsistencyBase

Data version

5.2

Document digest

6cfe13cef68f7d5c05ffd128d1e072d20a184c9fa0301a6c1df1f9dff40ef040

05 Affected products

VendorProductVersionsPlatforms

armmbed_tlsNot specified—

debiandebian_linuxNot specified—

06 References

github.comhttps://github.com/ARMmbed/mbedtls/issues/5136
lists.debian.org[debian-lts-announce] 20221225 [SECURITY] [DLA 3249-1] mbedtls security updatehttps://lists.debian.org/debian-lts-announce/2022/12/msg00036.htmlmailing-list
lists.debian.orghttps://lists.debian.org/debian-lts-announce/2025/06/msg00034.html

01 Record index

CVE-2021-43666

02 Description

03 Exploitation and scoring

04 Metadata

05 Affected products

06 References

02 Records

CVE-2021-43666

02 Description

03 Exploitation and scoring

04 Metadata

05 Affected products

06 References