CVE-2021-29923

moderate-risk
Published 2021-08-07

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.

Do I need to act?

-
0.25% chance of exploitation
EPSS score — low exploit probability
-
Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
7
CVSS 7.5/10 High
NETWORK / LOW complexity

Affected Products (3)

Go

Affected Vendors

Oracle Fedoraproject Golang

References (18)

Third Party Advisory https://defcon.org/html/defcon-29/dc-29-speakers.html#kaoudis
Exploit https://github.com/golang/go/issues/30999
Issue Tracking https://github.com/golang/go/issues/43389
Exploit https://github.com/sickcodes/security/blob/master/advisories/SICK-2021-016.md
Patch https://go-review.googlesource.com/c/go/+/325829/
Vendor Advisory https://golang.org/pkg/net/#ParseCIDR
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro...
Third Party Advisory https://security.gentoo.org/glsa/202208-02
Patch https://www.oracle.com/security-alerts/cpujan2022.html
Third Party Advisory https://defcon.org/html/defcon-29/dc-29-speakers.html#kaoudis
Exploit https://github.com/golang/go/issues/30999
Issue Tracking https://github.com/golang/go/issues/43389
Exploit https://github.com/sickcodes/security/blob/master/advisories/SICK-2021-016.md
Patch https://go-review.googlesource.com/c/go/+/325829/
Vendor Advisory https://golang.org/pkg/net/#ParseCIDR
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro...
Third Party Advisory https://security.gentoo.org/glsa/202208-02
Patch https://www.oracle.com/security-alerts/cpujan2022.html
36
/ 100
moderate-risk
Severity 26/34 · High
Exploitability 1/34 · Minimal
Exposure 9/34 · Low