CVE-2021-4437

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.
• AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
• 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

0.45% probability of exploitation activity in the next 30 days.

EPSS percentile

Ranks above 37.0% of scored records. A rank, not a probability.

NVD base score

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

NVD CVSS vector

CVSS:3.1/AV:A/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.

Published

2024-02-12 19:31Z2 YR AGO

Last updated

2025-05-06 18:44Z1 YR AGO

Reserved

2024-02-11

Assigning CNA

VulDB

Record state

PUBLISHED

Severity

Low (CVSS 3.5)

CNA CVSS vector

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

Weaknesses

• CWE-1333Inefficient Regular Expression ComplexityBase

Data version

5.1

Document digest

adce5c3b99311e985310e7a1fab06278b7ef07310c4430dc2b03be44c898435e

• vuldb.comhttps://vuldb.com/?id.253406vdb-entry
• vuldb.comhttps://vuldb.com/?ctiid.253406signaturepermissions-required
• github.comhttps://github.com/dbartholomae/lambda-middleware/pull/57issue-tracking
• github.comhttps://github.com/dbartholomae/lambda-middleware/commit/f689404d830cbc1edd6a1018d3334ff5f44dc6a6patch
• github.comhttps://github.com/dbartholomae/lambda-middleware/releases/tag/%40lambda-middleware%2Fframeguard_v1.1.0patch