CVE-2021-29923
CVSS v3
7.5
HIGH
EPSS Score
3.7 %
exploit probability, as of 2026-09-25
CISA KEV
No
known exploited
Exploitation
—
SSVC status
Description
Go before 1.17 does not properly consider extraneous zero characters at the beginning of an IP address octet, which (in some situations) allows attackers to bypass access control that is based on IP addresses, because of unexpected octal interpretation. This affects net.ParseIP and net.ParseCIDR.
Technical details
- Published
- 2021-08-07
Frequently asked questions
What is CVE-2021-29923?
Go before 1.17 does not properly consider extraneous zero characters at the beginning of an IP address octet, which (in some situations) allows attackers to bypass access control that is based on IP addresses, because of unexpected octal interpretation. This affects net.ParseIP and net.ParseCIDR.
Is CVE-2021-29923 actively exploited?
Active exploitation of CVE-2021-29923 has not been confirmed. Its EPSS score was 3.7% on 2026-09-25, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2021-29923?
CVE-2021-29923 has a CVSS v3 base score of 7.5 (HIGH severity).
Is CVE-2021-29923 affecting your environment?
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