CVE-2021-29921

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

6.88% probability of exploitation activity in the next 30 days.

EPSS percentile

Ranks above 93.5% of scored records. A rank, not a probability.

NVD base score

9.8 (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:H/I:H/A:H

NVD analysis status

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

Red Hat severity

Moderate. Red Hat's rating for its own products, not a CVSS rating.

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

2021-05-06 00:00Z5 YR AGO

Last updated

2025-11-03 21:44Z10 MO AGO

Reserved

2021-04-01

Assigning CNA

mitre

Record state

PUBLISHED

Severity

Not rated by the issuing CNA

CNA CVSS vector

Not published by the issuing CNA

Weaknesses

• CWE-20Improper Input ValidationClass

Data version

5.2

Document digest

365c7c58f8c3d4874e0c7d999f23b20825362e10f3e8e0d4a5b26fe8fa9d3940

• github.comhttps://github.com/sickcodes
• docs.python.orghttps://docs.python.org/3/library/ipaddress.html
• github.comhttps://github.com/python/cpython/blob/63298930fb531ba2bb4f23bc3b915dbf1e17e9e1/Misc/NEWS.d/3.8.0a4.rst
• sick.codeshttps://sick.codes/sick-2021-014
• www.oracle.comhttps://www.oracle.com//security-alerts/cpujul2021.html
• github.comhttps://github.com/sickcodes/security/blob/master/advisories/SICK-2021-014.md
• python-security.readthedocs.iohttps://python-security.readthedocs.io/vuln/ipaddress-ipv4-leading-zeros.html
• bugs.python.orghttps://bugs.python.org/issue36384
• github.comhttps://github.com/python/cpython/pull/12577
• github.comhttps://github.com/python/cpython/pull/25099
• security.netapp.comhttps://security.netapp.com/advisory/ntap-20210622-0003/
• www.oracle.comhttps://www.oracle.com/security-alerts/cpuoct2021.html
• www.oracle.comhttps://www.oracle.com/security-alerts/cpujan2022.html
• www.oracle.comhttps://www.oracle.com/security-alerts/cpuapr2022.html
• www.oracle.comhttps://www.oracle.com/security-alerts/cpujul2022.html
• security.gentoo.orgGLSA-202305-02https://security.gentoo.org/glsa/202305-02vendor-advisory
• lists.debian.orghttps://lists.debian.org/debian-lts-announce/2024/12/msg00000.html