CVE-2026-2869 identifies a security vulnerability in the janet-lang janet interpreter, versions 1.40.0 and 1.40.1, caused by an out-of-bounds read in the janetc_varset function located in src/core/specials.c, part of the handleattr Handler component. The vulnerability arises when the function improperly handles memory boundaries, allowing an attacker with local access and low privileges to read memory outside the allocated buffer. This can lead to unauthorized disclosure of sensitive data residing in adjacent memory areas. The attack vector is local, requiring the attacker to have some level of access to the system where janet is running, but no user interaction or elevated privileges are necessary. The flaw does not affect confidentiality, integrity, or availability directly beyond information disclosure. The vendor addressed this issue in janet version 1.41.0, with the patch identified by commit 2fabc80151a2b8834ee59cda8a70453f848b40e5. While an exploit is publicly available, there are no confirmed reports of exploitation in the wild, indicating limited active threat. The vulnerability has a CVSS 4.8 score, reflecting medium severity due to the local attack vector and limited impact scope.

The primary impact of CVE-2026-2869 is unauthorized information disclosure through out-of-bounds memory reads. For organizations, this could mean leakage of sensitive data such as cryptographic keys, credentials, or other confidential information stored in memory adjacent to the vulnerable buffer. Since exploitation requires local access with low privileges, the threat is mainly to environments where untrusted users have local system access, such as shared hosting, multi-tenant systems, or developer workstations. The vulnerability does not allow remote exploitation, privilege escalation, or denial of service, limiting its overall impact. However, in high-security environments or where janet-lang is used in critical applications, even limited data exposure can be significant. The availability of a public exploit increases the risk of opportunistic attacks by local adversaries or malicious insiders. Organizations relying on janet-lang janet should consider the risk in their threat models, especially if the interpreter is used in multi-user or sensitive contexts.

To mitigate CVE-2026-2869, organizations should upgrade janet-lang janet to version 1.41.0 or later, where the vulnerability is patched. Additionally, restrict local access to systems running vulnerable versions to trusted users only, minimizing the risk of exploitation by unprivileged attackers. Implement strict access controls and monitoring on systems where janet is deployed, especially in shared or multi-tenant environments. Employ memory protection mechanisms such as Address Space Layout Randomization (ASLR) and Data Execution Prevention (DEP) to reduce the likelihood of successful exploitation. Regularly audit and review local user privileges to ensure minimal necessary access. Finally, monitor security advisories and threat intelligence feeds for any emerging exploitation attempts or related vulnerabilities in janet-lang.