CVE-2021-20266 Denial of service in rpm
Medium 4.9
Published
Updated
Check this codebase for CVE-2021-20266 and fix it if it is affected.
What it is: CVE-2021-20266 is a medium-severity denial of service vulnerability in Fedoraproject Fedora, published on 30 Apr 2021. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-20266 in the wild and no public exploit code.
Affected product: Fedoraproject Fedora. No package-level version data is available, so check the vendor advisory linked from the reference page.
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-2021-20266/ (Markdown: https://insights.sbomify.com/CVE-2021-20266/index.md)
An attacker with rpmdb modification access can trigger an out-of-bounds read in RPM, causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2021-20266?
CVE-2021-20266 is a medium-severity denial of service vulnerability in Fedoraproject Fedora, published on 30 Apr 2021. An attacker needs administrator access to exploit it, with no action from the victim.
Official description
A flaw was found in RPM's hdrblobInit() in lib/header.c. This flaw allows an attacker who can modify the rpmdb to cause an out-of-bounds read. The highest threat from this vulnerability is to system availability.
Weakness: CWE-125
Which versions are affected by CVE-2021-20266?
It affects 2 products.
Linux distribution packages (40)
rpm-build AlmaLinux:8 | All versions | 4.14.3-19.el8 |
rpm-plugin-fapolicyd AlmaLinux:8 | All versions | 4.14.3-19.el8 |
python3-rpm-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 0:4.14.3-19.el8 |
rpm-build Red Hat:enterprise_linux:8::appstream | All versions | 0:4.14.3-19.el8 |
rpm-build-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 0:4.14.3-19.el8 |
rpm-build-libs-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 0:4.14.3-19.el8 |
rpm-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 0:4.14.3-19.el8 |
rpm-debugsource Red Hat:enterprise_linux:8::appstream | All versions | 0:4.14.3-19.el8 |
rpm-devel-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 0:4.14.3-19.el8 |
rpm-libs-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 0:4.14.3-19.el8 |
rpm-plugin-fapolicyd Red Hat:enterprise_linux:8::appstream | All versions | 0:4.14.3-19.el8 |
rpm-plugin-fapolicyd-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 0:4.14.3-19.el8 |
rpm-plugin-ima-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 0:4.14.3-19.el8 |
rpm-plugin-prioreset-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 0:4.14.3-19.el8 |
rpm-plugin-selinux-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 0:4.14.3-19.el8 |
rpm-plugin-syslog-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 0:4.14.3-19.el8 |
rpm-plugin-systemd-inhibit-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 0:4.14.3-19.el8 |
rpm-sign-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 0:4.14.3-19.el8 |
python3-rpm Red Hat:enterprise_linux:8::baseos | All versions | 0:4.14.3-19.el8 |
python3-rpm-debuginfo Red Hat:enterprise_linux:8::baseos | All versions | 0:4.14.3-19.el8 |
rpm Red Hat:enterprise_linux:8::baseos | All versions | 0:4.14.3-19.el8 |
rpm-apidocs Red Hat:enterprise_linux:8::baseos | All versions | 0:4.14.3-19.el8 |
rpm-build-debuginfo Red Hat:enterprise_linux:8::baseos | All versions | 0:4.14.3-19.el8 |
rpm-build-libs Red Hat:enterprise_linux:8::baseos | All versions | 0:4.14.3-19.el8 |
rpm-build-libs-debuginfo Red Hat:enterprise_linux:8::baseos | All versions | 0:4.14.3-19.el8 |
rpm-cron Red Hat:enterprise_linux:8::baseos | All versions | 0:4.14.3-19.el8 |
rpm-debuginfo Red Hat:enterprise_linux:8::baseos | All versions | 0:4.14.3-19.el8 |
rpm-debugsource Red Hat:enterprise_linux:8::baseos | All versions | 0:4.14.3-19.el8 |
rpm-devel Red Hat:enterprise_linux:8::baseos | All versions | 0:4.14.3-19.el8 |
rpm-devel-debuginfo Red Hat:enterprise_linux:8::baseos | All versions | 0:4.14.3-19.el8 |
rpm-libs Red Hat:enterprise_linux:8::baseos | All versions | 0:4.14.3-19.el8 |
rpm-libs-debuginfo Red Hat:enterprise_linux:8::baseos | All versions | 0:4.14.3-19.el8 |
rpm-plugin-fapolicyd-debuginfo Red Hat:enterprise_linux:8::baseos | All versions | 0:4.14.3-19.el8 |
rpm-plugin-ima Red Hat:enterprise_linux:8::baseos | All versions | 0:4.14.3-19.el8 |
rpm-plugin-ima-debuginfo Red Hat:enterprise_linux:8::baseos | All versions | 0:4.14.3-19.el8 |
rpm-plugin-prioreset Red Hat:enterprise_linux:8::baseos | All versions | 0:4.14.3-19.el8 |
rpm-plugin-prioreset-debuginfo Red Hat:enterprise_linux:8::baseos | All versions | 0:4.14.3-19.el8 |
rpm-plugin-selinux Red Hat:enterprise_linux:8::baseos | All versions | 0:4.14.3-19.el8 |
rpm-plugin-selinux-debuginfo Red Hat:enterprise_linux:8::baseos | All versions | 0:4.14.3-19.el8 |
rpm-plugin-syslog Red Hat:enterprise_linux:8::baseos | All versions | 0:4.14.3-19.el8 |
Products include Fedoraproject Fedora, Rpm Rpm.
How do I fix CVE-2021-20266?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2021-20266 being exploited?
There is no known exploitation of CVE-2021-20266 in the wild and no public exploit code.
Other vulnerabilities in Fedoraproject Fedora
Sources
Also known as ALSA-2021:4489, DEBIAN-CVE-2021-20266, GHSA-8vf3-43pf-v3cq, RHSA-2021:4489, RLSA-2021:4489, UBUNTU-CVE-2021-20266.