How We Mitigate CVEs in Modern Container Images (2025 Guide)
| CVE ID | Component / Package | Underlying OS | Issue Summary | Resolution Taken | Resolved In Version | Backported (OEL/OEL-like OS)? |
|---|---|---|---|---|---|---|
| CVE-2024-3094 | xz-utils (XZ backdoor) | UBI 9.6 (RHEL-based) | Malicious backdoor in liblzma affecting SSH authentication | Updated base image to UBI 9.6 which already ships patched xz-utils. Rebuilt Keycloak image on top of patched OS. | UBI 9.6 (March 2024 update) | ✔ Yes — Red Hat/Oracle backported fix to stable branches |
| CVE-2024-6387 | OpenSSH regreSSHion | UBI 9.6 | Remote unauthenticated RCE via signal handling race condition | Base OS updated (dnf update) ensuring OpenSSH patched. No application changes needed. | UBI 9.5+ (July 2024) | ✔ Yes |
| CVE-2024-0727 | glibc | UBI 9.6 | Buffer overflow during dynamic loader processing | Patched via OS-level update when rebuilding Keycloak container. | glibc-2.34-100+ | ✔ Yes |
| CVE-2023-0464 | OpenSSL | UBI/OEL | DoS in X.400 address parsing | Resolved via base image patching; OpenSSL auto-updated during container rebuild | OpenSSL 3.0.7+ | ✔ Yes |
| CVE-2022-40674 | ncurses | UBI/OEL | Heap corruption in tic/infocmp utilities | Updated via latest UBI packages; not required to rebuild app layer | ncurses-6.2+ | ✔ Yes |
| CVE-2023-42378 | BusyBox | Container runtime | Integer overflow in ash/applet utilities | Updated BusyBox from UBI repo; no manual patching | BusyBox 1.36+ | ✔ Yes |
| Multiple (2023–2024) | shadow-utils | UBI/OEL | Password handling & chfn validation bugs | Resolved via base OS update during container rebuild | shadow-utils-4.9+ | ✔ Yes |
| Multiple (2023–2024) | Kernel-related CVEs | UBI/OEL | Privilege escalation/syscall bugs | Automatically patched via UBI kernel packages; container inherits fixes | Kernel release of UBI 9.6 | ✔ Yes |
| CVE-2023-40217 | systemd | UBI | OOB read vulnerability in DNS resolver | Patched with systemd update in UBI | systemd-252+ | ✔ Yes |
| CVE-2023-26604 | polkit | UBI/OEL | Local privilege escalation | Eliminated via OS updates; container rebuild includes fix | polkit-0.120+ | ✔ Yes |
Keeping container images secure is one of the most important responsibilities in modern DevOps and cloud-native environments. CVEs (Common Vulnerabilities and Exposures) frequently affect the underlying OS packages such as glibc, OpenSSL, OpenSSH, BusyBox, ncurses, systemd, and more.
If these vulnerabilities are not mitigated, even a fully updated application stack can remain exposed.
This guide explains how our container hardening and CVE-mitigation workflow ensures production-grade security, following enterprise best-practices.
🔐 1. Start With a Secure & Updated Base Image
A container is only as secure as its base layer.
We begin with a hardened and actively maintained OS image:
- Red Hat UBI 9.6
- Or UEL/OEL (Oracle Enterprise Linux) where backported fixes are guaranteed
Using updated images ensures that major CVEs—such as the XZ Backdoor (CVE-2024-3094) and OpenSSH regreSSHion (CVE-2024-6387)—are already patched at the OS level.
🔧 2. Apply OS-Level Security Patches
Before adding any application logic, we fully update the OS:
dnf -y updateThis single step patches:
- glibc
- openssl
- systemd
- busybox
- ncurses
- shadow-utils
- kernel packages
- OpenSSH
and all other vulnerable packages.
This ensures the image inherits backported enterprise security fixes without breaking compatibility.
🏗️ 3. Rebuild Application Runtime on Patched OS
We layer the application (e.g., Keycloak, Java, Node runtimes, microservices) after patching the base OS.
This ensures:
- No vulnerable libraries survive in the lower layers
- No old dependencies sneak in through build tools
- The final runtime is fully aligned with patched system libraries
🧹 4. Remove Insecure Build Tools
To reduce the attack surface:
- No podman/buildah in final image
- No dev compilers
- No container-build utilities
- No unnecessary CLI tools
This minimizes the risk of container breakout or privilege escalation vulnerabilities.
📌 5. Validate Backported Fixes (RHEL/OEL/UBI Rule)
Enterprise Linux distros backport security patches without changing version numbers.
This means:
- You get the fix
- Without upgrading to breaking major versions
This is ideal for production workloads.
🎯 Summary
By combining:
- A hardened base OS
- OS-level security updates
- Runtime rebuild on patched layers
- Removal of unsafe tooling
- Verification of backports
we ensure that container images remain secure, stable, and compliant with enterprise security best-practices.
2. Downloadable PDF
Download here:
👉 CVE_Mitigation_Guide.pdf
3. Graphical Diagram (Included inside PDF)
Below is the visual logic that the PDF also contains:
[CVE Detected] → [OS Patch Applied] → [Container Rebuilt] → [Final Secure Runtime