VulnerabilityPublished 23 Nov 2025Updated 24 Nov 2025

CVE-2025-13566: jarun nnn · Double Free

Affects jarun nnnSource CVE Database V5

Not known to be exploited · CVSS 4.8 Medium.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 4.0 base score

4.8Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X

Attack Vector: Local
Attack Complexity: Low
Attack Requirements: None
Privileges Required: Low
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: None
Vulnerable system availability: Low
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Local: The vulnerable system is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or through terminal emulation (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., using social engineering techniques to trick a legitimate user into opening a malicious document).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: Low: The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the Vulnerable System are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 23 Nov 2025
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.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
GitHubjarun/nnn`pkg:github/jarun/nnn`Other threats	Affected =5.0 =5.1	Fixed in–

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

AI-suggested

To mitigate CVE-2025-13566, European organizations should: 1) Immediately apply the patch identified by commit 2f07ccdf21e705377862e5f9dfa31e1694979ac7 from the official 'nnn' repository or vendor updates. 2) Restrict local access to systems running 'nnn' to trusted users only, minimizing the risk of local exploitation. 3) Implement strict user privilege management and monitor for unusual local activity that could indicate exploitation attempts. 4) Employ memory protection mechanisms such as Address Space Layout Randomization (ASLR) and stack canaries to reduce exploitation success. 5) Regularly audit installed software versions and remove or replace unused or unnecessary tools like 'nnn' in sensitive environments. 6) Educate users about the risks of running untrusted commands or plugins within 'nnn' to avoid triggering the vulnerable code paths. 7) Integrate vulnerability scanning and patch management processes to ensure timely updates of open-source tools.

Description

A security vulnerability has been detected in jarun nnn up to 5.1. The impacted element is the function show_content_in_floating_window/run_cmd_as_plugin of the file nnn/src/nnn.c. The manipulation leads to double free. An attack has to be approached locally. The identifier of the patch is 2f07ccdf21e705377862e5f9dfa31e1694979ac7. It is suggested to install a patch to address this issue.

Impact

For European organizations, the impact of CVE-2025-13566 is primarily related to potential denial of service or local privilege escalation on systems where 'nnn' is installed and used. Since exploitation requires local access, the threat is higher in environments with multiple users or where untrusted users have shell access. Organizations relying on 'nnn' for file management in development, system administration, or automation tasks could face disruptions if the vulnerability is exploited. While no remote exploitation is possible, insider threats or compromised accounts could leverage this flaw to destabilize systems or escalate privileges. The impact on confidentiality is minimal, but integrity and availability could be affected due to memory corruption. European entities with strong open-source usage, especially in IT, research, and development sectors, may be more exposed. The absence of known exploits reduces immediate risk but does not eliminate the need for timely patching to prevent future attacks.

References

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