CVE-2026-2703 | xlnt-community xlnt up to 1.6.1 Encrypted XLSX File Parser base64.cpp decode_base64 off-by-one (Issue 137)

A vulnerability categorized as problematic has been discovered in xlnt-community xlnt up to 1.6.1. Impacted is the function xlnt::detail::decode_base64 of the file source/detail/cryptography/base64.cpp of the component Encrypted XLSX File Parser. Executing a manipulation can lead to off-by-one.

This vulnerability appears as CVE-2026-2703. The attack requires local access. In addition, an exploit is available.

Applying a patch is advised to resolve this issue.