# CVE-2021-29923: Security feature bypass in n/a > Attackers can bypass IP-based access controls by using leading zeros in IP addresses, affecting Go applications using net.ParseIP or net.ParseCIDR. - **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 7 Aug 2021 - **Updated:** 3 Aug 2024 - **Also known as:** AZL-79056, AZL-98910, BIT-golang-2021-29923, DEBIAN-CVE-2021-29923, GHSA-38h6-vxp4-qxvm, RHSA-2021:3585, RHSA-2021:4910, RHSA-2022:0989, RHSA-2022:0997, RLSA-2021:3585, UBUNTU-CVE-2021-29923 ## What is CVE-2021-29923? CVE-2021-29923 is a high-severity vulnerability in Fedoraproject Fedora, published on 7 Aug 2021. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official 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. ## Which versions are affected by CVE-2021-29923? 1 open source package ship an affected version, including golang. It affects 3 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `golang` | Bitnami | All versions | 1.17.0 | | `kubevirt` | Red Hat:container_native_virtualization:4.8::el7 | All versions | 0:4.8.3-251.el7 | | `kubevirt-virtctl` | Red Hat:container_native_virtualization:4.8::el7 | All versions | 0:4.8.3-251.el7 | | `kubevirt-virtctl-redistributable` | Red Hat:container_native_virtualization:4.8::el7 | All versions | 0:4.8.3-251.el7 | | `kubevirt` | Red Hat:container_native_virtualization:4.8::el8 | All versions | 0:4.8.3-251.el8 | | `kubevirt-virtctl` | Red Hat:container_native_virtualization:4.8::el8 | All versions | 0:4.8.3-251.el8 | | `kubevirt-virtctl-redistributable` | Red Hat:container_native_virtualization:4.8::el8 | All versions | 0:4.8.3-251.el8 | | `delve` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.5.0-2.module+el8.4.0+8864+58b0fcdb | | `delve-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.5.0-2.module+el8.4.0+8864+58b0fcdb | | `delve-debugsource` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.5.0-2.module+el8.4.0+8864+58b0fcdb | | `go-toolset` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.15.14-2.module+el8.4.0+12542+e3fec473 | | `golang` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.15.14-2.module+el8.4.0+12542+e3fec473 | | `golang-bin` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.15.14-2.module+el8.4.0+12542+e3fec473 | | `golang-docs` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.15.14-2.module+el8.4.0+12542+e3fec473 | | `golang-misc` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.15.14-2.module+el8.4.0+12542+e3fec473 | | `golang-race` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.15.14-2.module+el8.4.0+12542+e3fec473 | | `golang-src` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.15.14-2.module+el8.4.0+12542+e3fec473 | | `golang-tests` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.15.14-2.module+el8.4.0+12542+e3fec473 | | `golang-qpid-apache` | Red Hat:openstack:16.1::el8 | All versions | 0:0.32.0-rc1.9.el8ost | | `golang-qpid-apache` | Red Hat:openstack:16.2::el8 | All versions | 0:0.32.0-rc1.9.el8ost | | `delve` | Rocky Linux:8 | All versions | 0:1.5.0-2.module+el8.4.0+396+d2d16ae3 | | `go-toolset` | Rocky Linux:8 | All versions | 0:1.15.14-2.module+el8.4.0+646+fc1a61b2 | | `golang` | Rocky Linux:8 | All versions | 0:1.15.14-2.module+el8.4.0+646+fc1a61b2 | Products: Fedoraproject Fedora, Golang Go, Oracle Timesten In-Memory Database. ## How do I fix CVE-2021-29923? Upgrade golang to 1.17.0 or later. ## Is CVE-2021-29923 being exploited? There is no known exploitation of CVE-2021-29923 in the wild and no public exploit code. ## Other vulnerabilities in Fedoraproject Fedora - [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild) - [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild) - [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild) - [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild) - [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2021-29923 and fix it if it is affected. What it is: CVE-2021-29923 is a high-severity vulnerability in Fedoraproject Fedora, published on 7 Aug 2021. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2021-29923 in the wild and no public exploit code. Affected packages and fixed versions: - golang (Bitnami): affected all versions; fixed in 1.17.0 Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2021-29923/ (Markdown: https://insights.sbomify.com/CVE-2021-29923/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2021-29923 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-29923 - OSV: https://osv.dev/vulnerability/CVE-2021-29923 --- From sbomify Insights: https://insights.sbomify.com/CVE-2021-29923/ Summaries are generated and may contain mistakes; the official description above is the record.