CVE-2026-38754
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceA heap overflow vulnerability exists in the ifsbreakup() function within shell/ash.c of Busybox v1.38.0. The function fails to properly validate or bound-check input when processing Internal Field Separator (IFS) data, allowing an attacker to overflow the heap buffer by supplying specially crafted input, leading to denial of service.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data= 1.38.0CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- None
- Availability
- Low
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Locate Busybox binaryRun 'which busybox' or 'command -v busybox' to find the executable pathAffected if Busybox is not found on the system - the vulnerability only applies if Busybox is installed
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Get Busybox versionRun 'busybox --version' or 'busybox -v' to retrieve the installed version numberAffected if The version displayed is exactly 1.38.0 - this is the only affected version per the CVE
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Check if ash shell is enabledRun 'busybox --list | grep ash' or 'busybox --help' to see if ash (the Almquist shell) is compiled in as a built-inAffected if ash is not available - the vulnerability exists in shell/ash.c, so ash must be enabled for the flaw to apply
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Verify ash is being used as the system shellCheck the default shell with 'echo $SHELL' or inspect /etc/passwd entries to see if ash or 'sh' points to Busybox ashAffected if ash is not the active shell - the vulnerability is only exploitable when ash processes IFS data
You are affected only if Busybox version is exactly 1.38.0 AND the ash shell is enabled and actively processing IFS data in your environment
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataUpgrade Busybox to a version beyond v1.38.0 that patches the ifsbreakup() function with proper bounds checking and input validation, or apply a vendor-supplied patch that adds heap boundary checks to prevent the overflow.
- Consultation2.0 h
- Implementation4.0 h
- Testing6.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,808.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-38754 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-38754 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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