CVE-2021-34991

Exploitation

Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.

SSVC decision

Not assessed by CISA

EPSS probability

5.67% probability of exploitation activity in the next 30 days.

EPSS percentile

Ranks above 92.3% of scored records. A rank, not a probability.

NVD base score

8.8 (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:H/I:H/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

2021-11-15 15:40Z4 YR AGO

Last updated

2024-08-04 00:26Z2 YR AGO

Reserved

2021-06-17

Assigning CNA

zdi

Record state

PUBLISHED

Severity

High (CVSS 8.8)

CNA CVSS vector

CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Weaknesses

• CWE-121Stack-based Buffer OverflowVariant
• CWE-787Out-of-bounds WriteBase

Data version

5.1

Document digest

7f86143e9b751ffff1995fd96f77715cd77038cb7160dbead1db95d6b3f4cc30

• www.zerodayinitiative.comhttps://www.zerodayinitiative.com/advisories/ZDI-21-1303/x_refsource_MISC
• kb.netgear.comhttps://kb.netgear.com/000064361/Security-Advisory-for-Pre-Authentication-Buffer-Overflow-on-Multiple-Products-PSV-2021-0168x_refsource_MISC