CVE-2025-7707: 
LlamaIndex vulnerability analysis and mitigation

The llama_index library version 0.12.33 contains a security vulnerability identified as CVE-2025-7707. The vulnerability stems from the library's default configuration which sets the NLTK data directory to a subdirectory of the codebase that is world-writable in multi-user environments. This vulnerability was discovered and disclosed on October 13, 2025, affecting all installations of llama_index version 0.12.33 (NVD).

The vulnerability arises from the use of a shared cache directory instead of a user-specific one for NLTK data storage. The CVSS v3.1 base score is 7.8 (High), with the vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. This indicates a local attack vector with low attack complexity, requiring low privileges and no user interaction. The vulnerability has been classified under CWE-377 (Insecure Temporary File) (NVD, AttackerKB).

The vulnerability allows local users to overwrite, delete, or corrupt NLTK data files, potentially leading to denial of service, data tampering, or privilege escalation in multi-user environments. The impact scores indicate high severity across confidentiality, integrity, and availability (NVD).

The vulnerability is exploitable by local users with low privileges. No user interaction is required for exploitation, and the attack complexity is considered low. The vulnerability has been documented with proof-of-concept code available (Huntr).

A patch has been released in version 0.13.0 of llama_index that addresses this vulnerability. Users are advised to upgrade to this version or later. The fix involves changing the NLTK data directory configuration to use user-specific paths (Github Patch).