CVE Intelligence
Medium Memory corruption

CVE-2026-6390 — Nano: gnu nano: arbitrary memory writes, information disclosure, or denial of service via format string vulnerability in error handling.

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.

Published Jul 23, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: redhat

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.2% (30-day exploitation probability)+1
  • Technical severity (medium)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.15%
ahead of 4% of scored CVEs · Oct 15, 2026
Affects
Red Hat
Red Hat Enterprise Linux 10 and 5 more
CVSS base
6.8
Medium · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
None
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Total
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Red Hat Red Hat Enterprise Linux 10, Red Hat Red Hat Enterprise Linux 6, Red Hat Red Hat Enterprise Linux 7…).
  2. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  3. Exploitation requires user interaction: tighten email/web filtering and warn affected users.
  4. Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Red Hat Red Hat Enterprise Linux 10 versions not specified by the source Vulnerable CVE Program (cve.org) e CISA ADP
Red Hat Red Hat Enterprise Linux 6 versions not specified by the source Vulnerable CVE Program (cve.org) e CISA ADP
Red Hat Red Hat Enterprise Linux 7 versions not specified by the source Vulnerable CVE Program (cve.org) e CISA ADP
Red Hat Red Hat Enterprise Linux 8 versions not specified by the source Vulnerable CVE Program (cve.org) e CISA ADP
Red Hat Red Hat Enterprise Linux 9 versions not specified by the source Vulnerable CVE Program (cve.org) e CISA ADP
Red Hat Red Hat OpenShift Container Platform 4 versions not specified by the source Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
Required
Scope
Unchanged
Confidentiality
Low
Integrity
High
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
6.8 CVSS 3.1 Medium 1.3 5.5 secalert@redhat.com via NIST National Vulnerability Database
6.8 CVSS 3.1 Medium — — redhat via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:H/A:H (score shown at the top: secalert@redhat.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-134 · Use of Externally-Controlled Format String

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
  • Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
endpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · red hat/red hat enterprise linux 10, red hat/red hat enterprise linux 6, red hat/red hat enterprise linux 7, red hat/red
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 15, 2026
  • CVSS changed · 6.8
    Oct 15, 2026 · NIST National Vulnerability Database
  • Source status changed · → Awaiting Analysis
    Oct 15, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 15, 2026 · NIST National Vulnerability Database
  • CVE published
    Jul 23, 2026 · redhat

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

2 on the record

Elsewhere on this site

Red Hat
every CVE for this vendor
Memory corruption
same class
CWE-134
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-104715 Cifs-utils: mount.cifs credential-file option injection allows local privilege boundary bypass 4h
  • CVE-2026-92982 Ansible-operator-plugins: ansible operator plugins: arbitrary code execution via jinja2 template injection 19h
  • CVE-2026-110924 Openssh: openssh: gssapi delegated credentials can be stored after a failed authentication 21h
  • CVE-2026-110927 Openssh: openssh: a compressed payload can expand past the maximum packet size 21h
  • CVE-2026-110926 Openssh: openssh: shared lz77 compression dictionary leaks plaintext across channels 1d
  • CVE-2026-110923 Openssh: openssh: sftp can write outside the destination directory from a server-supplied path 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No fixed version, patch or mitigation documented.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-6390 is "Nano: gnu nano: arbitrary memory writes, information disclosure, or denial of service via format string vulnerability in error handling.", rated Medium. It affects Red Hat Enterprise Linux 10 (Red Hat); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 6.8 describes technical severity. EPSS 0.15% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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