Process crash via signed-overflow stack write
Published May 11, 2026 · Updated May 11, 2026
Out-of-bounds write in jqlang jq 1.8.1 and earlier allows local users to crash jq by converting an extremely long numeric string. The decNumberFromString path performs signed-int arithmetic in D2U(), lets a wrapped negative allocation size select a 30-byte stack buffer, and then writes attacker-controlled digit units far below the stack frame. Exploitation requires locally running a crafted filter and about 3.5 GiB of RAM; the demonstrated consequence is a SIGSEGV crash.
Summary
What happened
Out-of-bounds write in jqlang jq 1.8.1 and earlier allows local users to crash jq by converting an extremely long numeric string. The decNumberFromString path performs signed-int arithmetic in D2U(), lets a wrapped negative allocation size select a 30-byte stack buffer, and then writes attacker-controlled digit units far below the stack frame. Exploitation requires locally running a crafted filter and about 3.5 GiB of RAM; the demonstrated consequence is a SIGSEGV crash.
The record
- CVE
- CVE-2026-43894
- Published
- May 11, 2026
- Updated
- May 11, 2026
- Vendor
- jqlang
- Product
- jq
- Classifications
- CWE-190, T1499.004
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 11, 2026CVE publishedPublication date reported by the CVE source.
- May 11, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=<= 1.8.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
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
- D2U signed-overflow crash proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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