CVE-2026-38754 busybox vulnerability
A heap overflow in the ifsbreakup() function (shell/ash.c) of Busybox v1.38.0 allows attackers to cause a Denial of Service (DoS) via supplying a crafted input.
Quick answer
busybox should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- 1.38.0
Fixed versions
- Apply the latest vendor-supported patched version.
How to fix it
CVE-2026-38754 affects busybox and is rated high. A heap overflow in the ifsbreakup() function (shell/ash.c) of Busybox v1.38.0 allows attackers to cause a Denial of Service (DoS) via supplying a crafted input. Fix this first on internet-facing or admin systems. The practical fix is to upgrade to the latest vendor-supported patched release listed in the advisory, then verify the system is no longer exposed.
- Inventory every server, container, appliance, cluster, plugin, or device that uses busybox.
- Check the installed version and configuration against CVE-2026-38754 and the linked advisory.
- Apply the vendor fix: upgrade to the latest vendor-supported patched release listed in the advisory.
- Rebuild images, firmware, and appliances that include the affected BusyBox build.
- Disable or isolate the affected feature if you cannot update right away.
- Review crash logs, restarts, and error spikes that match the vulnerable component.
- Rotate secrets, rebuild affected systems, or reset sessions if you suspect compromise.
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Verify the fix
- Confirm busybox is running the patched version or the approved mitigation is active.
- Confirm affected public, admin, API, tunnel, or cluster access is limited to trusted users.
- Repeat the risky workflow or a safe test case and confirm the issue no longer appears.
- Review logs again after the fix for crashes, bypass attempts, file access, or suspicious changes.
- Save version, config, log, and scan evidence for your remediation record.
Related categories
Trusted references
FAQ
What is affected by CVE-2026-38754?
busybox versions listed as affected should be reviewed: 1.38.0.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.