Parsing-context corruption via option-stack off-by-one
Published Aug 4, 2026 · Updated Aug 4, 2026
Out-of-bounds write in popt on Red Hat Enterprise Linux and Hardened Images allows local users to corrupt application parsing context. poptStuffArgs admits a tenth nested or repeated insertion because its depth check omits one slot, advances optionStack beyond ten entries, and overwrites adjacent poptContext fields returned by poptGetArg functions. Code execution requires a host application to pass the corrupted string to exec, system, popen, dlopen, or an equivalent sink; without such a sink, impact is limited to parsing-state corruption or a host-process crash.
Summary
What happened
Out-of-bounds write in popt on Red Hat Enterprise Linux and Hardened Images allows local users to corrupt application parsing context. poptStuffArgs admits a tenth nested or repeated insertion because its depth check omits one slot, advances optionStack beyond ten entries, and overwrites adjacent poptContext fields returned by poptGetArg functions. Code execution requires a host application to pass the corrupted string to exec, system, popen, dlopen, or an equivalent sink; without such a sink, impact is limited to parsing-state corruption or a host-process crash.
The record
- CVE
- CVE-2026-18739
- Published
- Aug 4, 2026
- Updated
- Aug 4, 2026
- Vendor
- 389 Directory Server
- Product
- Red Hat Enterprise Linux 10
- Classifications
- CWE-787, T1203
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 4, 2026CVE publishedPublication date reported by the CVE source.
- Aug 4, 2026Record updatedLatest update available in the CVE record.
Exploitability
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Is a vulnerable build present?
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What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
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Technologies
Your stack
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Your stack
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