GNU nano creates the user’s ~/.local directory with overly permissive permissions when the...

Description

GNU nano creates the user’s ~/.local directory with overly permissive permissions when the directory does not exist yet. On first use of features requiring Cross-Desktop Group (XDG) data storage, nano explicitly requests directory mode 0777, making the directory world‑writable in environments where the process umask does not sufficiently restrict permissions.
In systems with a relaxed or zero umask, such as container environments, CI/CD runners, embedded systems, or user shells configured with umask 000, this results in ~/.local being created as world‑writable. A local attacker can exploit a race window between nano’s creation of ~/.local and its subsequent creation of more restrictive subdirectories to write attacker‑controlled files into the victim’s XDG directory hierarchy.

This problem was fixed in nano version 9.0

Basic information

Type
unreviewed
Severity
low
Advisory on GitHub
Open advisory ↗
Repository advisory
Source code
Not specified
Published (advisory)
2026-04-28 15:30:51 UTC
Updated
2026-04-28 15:30:58 UTC
NVD published
2026-04-28

EPSS Score

No EPSS score in this advisory JSON.

CVSS Scores

Base score Version Severity Vector
2.1 4.0
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Click to expand
Attack vector (AV:L)
Attacker needs local access on the target system.
Attack complexity (AC:L)
Exploitation conditions are straightforward and stable.
Attack requirements (AT:P)
Additional preconditions must be present for exploitation.
Privileges required (PR:N)
No privileges are required.
User interaction (UI:N)
No user interaction is required.
Vulnerable system confidentiality impact (VC:N)
No confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:L)
Limited integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:N)
No availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:N)
No confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:N)
No integrity impact on subsequent systems.
Subsequent system availability impact (SA:N)
No availability impact on subsequent systems.
Exploit maturity (threat) (E:X)
Not defined: no reliable threat intelligence; scoring assumes the worst case (equivalent to Attacked).
Confidentiality requirement (CR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Integrity requirement (IR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Availability requirement (AR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Modified attack vector (MAV:X)
Not defined: scoring uses the Base Attack Vector (AV).
Modified attack complexity (MAC:X)
Not defined: scoring uses the Base Attack Complexity (AC).
Modified attack requirements (MAT:X)
Not defined: scoring uses the Base Attack Requirements (AT).
Modified privileges required (MPR:X)
Not defined: scoring uses the Base Privileges Required (PR).
Modified user interaction (MUI:X)
Not defined: scoring uses the Base User Interaction (UI).
Modified vulnerable system confidentiality impact (MVC:X)
Not defined: scoring uses the Base VC metric.
Modified vulnerable system integrity impact (MVI:X)
Not defined: scoring uses the Base VI metric.
Modified vulnerable system availability impact (MVA:X)
Not defined: scoring uses the Base VA metric.
Modified subsequent system confidentiality impact (MSC:X)
Not defined: scoring uses the Base SC metric.
Modified subsequent system integrity impact (MSI:X)
Not defined: scoring uses the Base SI metric.
Modified subsequent system availability impact (MSA:X)
Not defined: scoring uses the Base SA metric.
Safety (supplemental) (S:X)
Not evaluated.
Automatable (supplemental) (AU:X)
Not evaluated.
Recovery (supplemental) (R:X)
Not evaluated.
Value density (supplemental) (V:X)
Not evaluated.
Vulnerability response effort (supplemental) (RE:X)
Not evaluated.
Provider urgency (supplemental) (U:X)
Not evaluated.

Identifiers

CWEs

CWE id Name
CWE-732 Incorrect Permission Assignment for Critical Resource

References

cvelogic Threat Intelligence