Shell crash via stale IFS region offsets
Published Jul 15, 2026 · Updated Jul 15, 2026
Out-of-bounds read in BusyBox ash 1.00 through 1.38.0 allows local users to crash a shell process with crafted input. An arithmetic expansion error can bypass ifsfree(), leaving stale IFS split offsets that ifsbreakup() later trusts while reading a shorter reused stack block. Exploitation requires the ash applet to process attacker-controlled shell input; the demonstrated consequence is a process crash and a one-byte out-of-bounds read.
Summary
What happened
Out-of-bounds read in BusyBox ash 1.00 through 1.38.0 allows local users to crash a shell process with crafted input. An arithmetic expansion error can bypass ifsfree(), leaving stale IFS split offsets that ifsbreakup() later trusts while reading a shorter reused stack block. Exploitation requires the ash applet to process attacker-controlled shell input; the demonstrated consequence is a process crash and a one-byte out-of-bounds read.
The record
- CVE
- CVE-2026-38754
- Published
- Jul 15, 2026
- Updated
- Jul 15, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-122, CWE-125, T1499.004
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 15, 2026CVE publishedPublication date reported by the CVE source.
- Jul 15, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- BusyBox ash stale IFS region reproducerproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo