CVE-2026-6390: A flaw was found in GNU nano's multi-buffer error mess
CVE-2026-6390 analysis covering impact, affected products, versions, remediation, and cross-checked defender guidance.
CVE-2026-6390 is a vulnerability published by NVD on 7/23/2026.
What happened
A flaw was found in GNU nano's multi-buffer error message handling. When a user opens multiple files at startup and one triggers an ALERT-level error, a specially crafted filename containing printf format specifiers can be reinterpreted. This format string vulnerability may allow an attacker to achieve stack information disclosure, cause a denial of service (crash), or potentially perform arbitrary memory writes.
Affected products and versions
- NVD has not published a normalized affected-product configuration yet.
Severity and weakness
CVSS: MEDIUM 6.8. Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:H/A:H.
Weaknesses: CWE-134.
Known exploitation
No CISA KEV entry is currently attached to the NVD record.
What defenders should do
- Identify whether the affected product and version range exists in production.
- Review vendor advisories and release notes before change windows.
- Patch, upgrade, disable the vulnerable component, or apply vendor mitigations.
- Verify the running version after deployment, not only the package inventory.
Official and supporting references
- No vendor advisory tagged by NVD at draft time.