EUVD-2026-62399
GHSA-2fq9-p2vj-rc2v
Severity by source
CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:A/VC:L/VI:L/VA:L/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
Local attack vector requiring low-privilege environment control and active victim interaction; impact bounded to a one-byte OOB access with no scope change.
Primary rating from Vendor (CERT-PL).
CVSS VectorVendor: CERT-PL
Lifecycle Timeline
1DescriptionCVE.org
nnn stores homelen variable as uchar_t, which can only represent values in the range 0-255. An attacker who can influence the victim's execution environment can provide an arbitrary HOME path with length that is truncated to 0. The expression (homelen - 1) is promoted to signed int and becomes -1 and producing an out-of-bounds read and an out-of-bounds write one byte before the path buffer.
Maintainer of this project was notified about this vulnerability. It might has been addressed, but the maintainer did not provide a vulnerable version range. Only version 5.2 was tested and confirmed as vulnerable.
AnalysisAI
Integer truncation in the nnn terminal file manager (version 5.2 confirmed vulnerable) allows a local attacker who controls the victim's HOME environment variable to trigger an out-of-bounds read and write. By supplying a HOME path longer than 255 characters, the uchar_t homelen variable wraps to zero; the expression (homelen - 1) promotes to signed int as -1, indexing one byte before the intended path buffer. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires that the attacker can set or manipulate the HOME environment variable in the victim's execution environment to a value exceeding 255 characters in length before the victim launches nnn. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 4.0 base score of 2.4 (AV:L/AC:L/AT:N/PR:L/UI:A) accurately characterizes this as a low-severity finding in practice. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | No vendor-released patch has been confirmed at time of analysis; the nnn maintainer was notified by CERT-PL but did not confirm a fixed version or a vulnerable version range. … Detailed patch versions, workarounds, and compensating controls in full report. |
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OS command injection in nnn file manager version 5.2 allows arbitrary shell command execution when a victim navigates to
Shell command injection in nnn file manager version 5.2 allows an attacker who controls a directory name on a shared fil
Out-of-bounds write in nnn terminal file manager version 5.2 allows a local attacker who can place a malicious session f
Same weakness CWE-197 – Numeric Truncation Error
View allSame technique Buffer Overflow
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External POC / Exploit Code
Leaving vuln.today