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VulnerabilityPublished Updated

CVE-2026-6390: GNU nano's multi-buffer error message handling

Affects nanoSource GCVE Database

0
Authoritative record:CVE-2026-6390· Medium 6.8

Not known to be exploited · CVSS 6.8 Medium · fixed in 6.2-1ubuntu0.2 : update nano when convenient.

Data as of 27 Oct 2026, 05:11 UTC

CVSS 3.1 base score
6.8Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 6.2-1ubuntu0.2, 7.2-2ubuntu0.2, 8.7.1-1ubuntu0.1 +1
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 23 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
Ubuntu 26.04 LTSnanopkg:deb/ubuntu/nano?arch=source&distro=resoluteOther threatsAffected
  • <8.7.1-1ubuntu0.1
Fixed in
  • 8.7.1-1ubuntu0.1
Ubuntu 25.10nanopkg:deb/ubuntu/nano?arch=source&distro=questingOther threatsAffected
  • <8.4-1ubuntu0.1
Fixed in
  • 8.4-1ubuntu0.1
Ubuntu 24.04 LTSnanopkg:deb/ubuntu/nano?arch=source&distro=nobleOther threatsAffected
  • <7.2-2ubuntu0.2
Fixed in
  • 7.2-2ubuntu0.2
Ubuntu 22.04 LTSnanopkg:deb/ubuntu/nano?arch=source&distro=jammyOther threatsAffected
  • <6.2-1ubuntu0.2
Fixed in
  • 6.2-1ubuntu0.2
Ubuntu Pro 20.04 LTSnanopkg:deb/ubuntu/nano?arch=source&distro=esm-infra/focalOther threatsAffected
  • 4.3-1 – 4.8-1ubuntu1.1+esm1
8 affected builds
Fixed in–
Ubuntu Pro 18.04 LTSnanopkg:deb/ubuntu/nano?arch=source&distro=esm-infra/bionicOther threatsAffected
  • 2.8.6-3 – 2.9.3-2ubuntu0.1~esm2
9 affected builds
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

If you cannot patch yet, avoid opening multiple files with untrusted or specially crafted filenames in GNU nano to reduce risk.

Description

A format string vulnerability exists in GNU nano's multi-buffer error message handling when opening multiple files at startup. If one file triggers an ALERT-level error and has a filename with printf format specifiers, this can lead to stack information disclosure, denial of service, or potentially arbitrary memory writes. The vulnerability affects multiple specific versions of GNU nano. The CVSS score is 6.8, indicating a medium severity level.

References

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