CVE-2021-31439

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

2.33% probability of exploitation activity in the next 30 days.

EPSS percentile

Ranks above 82.0% 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

2021-05-21 00:00Z5 YR AGO

Last updated

2024-08-03 22:55Z2 YR AGO

Reserved

2021-04-16

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-122Heap-based Buffer OverflowVariant
• CWE-787Out-of-bounds WriteBase

Data version

5.1

Document digest

b7c7a51941694439863fdd5c7cc5bf814978392487c82fb3db21029d6b2de305

• www.zerodayinitiative.comhttps://www.zerodayinitiative.com/advisories/ZDI-21-492/
• www.synology.comhttps://www.synology.com/zh-hk/security/advisory/Synology_SA_20_26
• lists.debian.org[debian-lts-announce] 20230516 [SECURITY] [DLA 3426-1] netatalk security updatehttps://lists.debian.org/debian-lts-announce/2023/05/msg00018.htmlmailing-list
• www.debian.orgDSA-5503https://www.debian.org/security/2023/dsa-5503vendor-advisory
• security.gentoo.orgGLSA-202311-02https://security.gentoo.org/glsa/202311-02vendor-advisory