nnn 5.2 Session File buffer overflow

Summaryinfo

A vulnerability marked as problematic has been reported in nnn 5.2. This vulnerability affects unknown code of the component Session File Handler. Performing a manipulation results in buffer overflow. This vulnerability was named CVE-2026-65609. The attack needs to be approached locally. There is no available exploit.

Detailsinfo

A vulnerability, which was classified as problematic, was found in nnn 5.2. This affects an unknown code of the component Session File Handler. The manipulation with an unknown input leads to a buffer overflow vulnerability. CWE is classifying the issue as CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

nnn is vulnerable to Out-of-Bound write vulnerability. Due to lack of validation of attacker-controlled length fields deserialized from a session file, a crafted session file can cause nnn to write data beyond the bounds of fixed-size global buffers when loaded with the -s option. An attacker who can place a malicious session file in the victim's nnn session directory can exploit this to corrupt adjacent global state. 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.

The advisory is shared at cert.pl. This vulnerability is uniquely identified as CVE-2026-65609 since 07/22/2026. The exploitability is told to be easy. An attack has to be approached locally. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/19/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Name

• nnn

Version

• 5.2

CPE 2.3info

• 🔒

CPE 2.2info

• 🔒

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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