CVE-2026-6390: GNU nano's multi-buffer error message handling
Affects nanoSource GCVE Database
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
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 23 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSnanopkg:deb/ubuntu/nano?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 25.10nanopkg:deb/ubuntu/nano?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSnanopkg:deb/ubuntu/nano?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 22.04 LTSnanopkg:deb/ubuntu/nano?arch=source&distro=jammyOther threats | Affected
| Fixed in
|
Ubuntu Pro 20.04 LTSnanopkg:deb/ubuntu/nano?arch=source&distro=esm-infra/focalOther threats | Affected
| Fixed in– |
Ubuntu Pro 18.04 LTSnanopkg:deb/ubuntu/nano?arch=source&distro=esm-infra/bionicOther threats | Affected
| 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.