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No exploitation reportedFix available

CVE-2021-29923

No exploitation reported by the sources we read.

  • Published2021-08-07
  • Fixed in1.17

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2021-08-0717:15CVE publishedNVD

Versions per branch

NVD
Go
BranchAffectedFixed in
1.17< 1.171.17
Fedoraproject fedora
BranchAffectedFixed in
36.x= 36no fix published
Oracle timesten in-memory database
BranchAffectedFixed in
21.1< 21.1.1.1.021.1.1.1.0

1 more product in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • butaneRed Hat:openshift:4.9::el8all versions · fixed in 0:0.13.1-2.rhaos4.9.el8and 3 other packages
  • cri-oRed Hat:openshift:4.9::el8all versions · fixed in 0:1.22.1-17.rhaos4.9.git3029b1d.2.el8and 2 other packages
  • cri-oRed Hat:openshift:4.9::el7all versions · fixed in 0:1.22.1-17.rhaos4.9.git3029b1d.el7and 1 other package
  • cri-toolsRed Hat:openshift:4.9::el8all versions · fixed in 0:1.22.0-2.el8and 2 other packages
  • delveRocky Linux:8all versions · fixed in 0:1.5.0-2.module+el8.4.0+396+d2d16ae3
  • delveRed Hat:enterprise_linux:8::appstreamall versions · fixed in 0:1.5.0-2.module+el8.4.0+8864+58b0fcdband 2 other packages
  • etcdRed Hat:openstack:16.2::el8all versions · fixed in 0:3.3.23-7.el8ostand 2 other packages
  • etcdRed Hat:openstack:16.1::el8all versions · fixed in 0:3.3.23-7.el8ostand 2 other packages

45 more package ranges on OSV.dev

Vendor advisories

  • CVE-2021-29923 Red Hat Product Security860 products fixed · 169 known affected

    golang: net: incorrect parsing of extraneous zero characters at the beginning of an IP address octet

    rhmtc/openshift-migration-must-gather-rhel8 as a component of Migration Toolkit for Containers · rhmtc/openshift-migration-registry-rhel8 as a component of Migration Toolkit for Containers · rhmtc/openshift-migration-velero-plugin-for-microsoft-azure-rhel8 as a component of Migration Toolkit for Containers · +166 more

  • RHSA-2022:1372 Red Hat Product Security72 products fixed

    Red Hat Security Advisory: Red Hat OpenShift Data Foundation 4.10.0 enhancement, security & bug fix update

  • RHSA-2022:1276 Red Hat Product Security31 products fixed

    Red Hat Security Advisory: Red Hat OpenShift Service Mesh 2.0.9 security update

  • RHSA-2022:0577 Red Hat Product Security2 products fixed

    Red Hat Security Advisory: Windows Container Support for Red Hat OpenShift 5.0.0 [security update]

  • RHSA-2022:0988 Red Hat Product Security3 products fixed

    Red Hat Security Advisory: Red Hat OpenStack Platform 16.1 (golang-github-vbatts-tar-split) security update

  • RHSA-2022:0989 Red Hat Product Security3 products fixed

    Red Hat Security Advisory: Red Hat OpenStack Platform 16.1 (golang-qpid-apache) security update

18 more advisories

Full record on NVD

Fix

  1. Update Go to 1.17
  2. Vendor fix Red Hat Product Security RHSA-2022:1372 · 72 productsFor details on how to apply this update, refer to: https://access.redhat.com/articles/11258
  3. Vendor fix Red Hat Product Security RHSA-2022:1276 · 31 productsThe OpenShift Service Mesh release notes provide information on the features and known issues: https://docs.openshift.com/container-platform/latest/service_mesh/v2x/servicemesh-release-notes.html
  4. Vendor fix Red Hat Product Security RHSA-2022:0577 · 2 productsFor Windows Machine Config Operator upgrades, see the following documentation: https://docs.openshift.com/container-platform/latest/windows_containers/windows-node-upgrades.html
  5. Vendor fix Red Hat Product Security RHSA-2022:0988 · 3 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
  6. Vendor fix Red Hat Product Security RHSA-2022:0947 · 2 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
  7. Vendor fix Red Hat Product Security RHSA-2022:0561 · 488 productsFor OpenShift Container Platform 4.9 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update: https://docs.openshift.com/container-platform/4.9/release_notes/ocp-4-9-r…

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Published
2021-08-07
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-38h6-vxp4-qxvm

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 2026-11-08, 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), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

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