Nano: gnu nano: arbitrary memory writes, information disclosure, or denial of service via format string vulnerability in error handling.
Summary
| CVE | CVE-2026-6390 |
|---|---|
| State | PUBLISHED |
| Assigner | redhat |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-07-23 05:16:38 UTC |
| Updated | 2026-07-23 15:33:09 UTC |
| Description | 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. |
Risk And Classification
Primary CVSS: v3.1 6.8 MEDIUM from [email protected]
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:H/A:H
EPSS: 0.001540000 probability, percentile 0.050190000 (date 2026-07-23)
Problem Types: CWE-134 | CWE-134 Use of Externally-Controlled Format String
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 6.8 | MEDIUM | CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:H/A:H |
| 3.1 | CNA | CVSS | 6.8 | MEDIUM | CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:H/A:H |
CVSS v3.1 Breakdown
Attack Vector
LocalAttack Complexity
LowPrivileges Required
LowUser Interaction
RequiredScope
UnchangedConfidentiality
LowIntegrity
HighAvailability
HighCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:H/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Red Hat | Red Hat Enterprise Linux 10 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 6 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 7 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 8 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 9 | Not specified | Not specified |
| CNA | Red Hat | Red Hat OpenShift Container Platform 4 | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| bugzilla.redhat.com/show_bug.cgi | [email protected] | bugzilla.redhat.com | |
| access.redhat.com/security/cve/CVE-2026-6390 | [email protected] | access.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-04-15T19:41:56.772Z | Reported to Red Hat. |
| CNA | 2026-07-22T00:00:00.000Z | Made public. |
Workarounds
CNA: Users should avoid opening untrusted files with GNU nano, especially those with filenames containing printf format specifiers (e.g., %s, %p, %n). This operational control helps prevent the exploitation of the format string vulnerability, which relies on specific filename content and error conditions during multi-buffer usage.
There are currently no legacy QID mappings associated with this CVE.