Memory writes, disclosure, and crashes via format string
Published Jul 23, 2026 · Updated Jul 23, 2026
Format string injection in GNU nano allows local users to disclose stack data, write memory, or crash the editor through a crafted filename. During multi-buffer startup, an ALERT-level error passes the filename back through printf-style formatting instead of treating it as data. Exploitation requires another user to open multiple files at startup, including the attacker-controlled name, and reach the error path.
Summary
What happened
Format string injection in GNU nano allows local users to disclose stack data, write memory, or crash the editor through a crafted filename. During multi-buffer startup, an ALERT-level error passes the filename back through printf-style formatting instead of treating it as data. Exploitation requires another user to open multiple files at startup, including the attacker-controlled name, and reach the error path.
The record
- CVE
- CVE-2026-6390
- Published
- Jul 23, 2026
- Updated
- Jul 23, 2026
- Vendor
- 389 Directory Server
- Product
- Red Hat Enterprise Linux 6
- Classifications
- CWE-134, CAPEC-135, T1204.002
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 23, 2026CVE publishedPublication date reported by the CVE source.
- Jul 23, 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?
Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.
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
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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