A weakness has been identified 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. The attack requires local access. The exploit has been made available to the public and could be used for attacks. This patch is called f2d7bf494e5c52706843cf7eb9892821bffb0734. Applying a patch is advised to resolve this issue.
https://vuldb.com/?submit.754377
https://vuldb.com/?ctiid.346649
https://github.com/xlnt-community/xlnt/issues/137
https://github.com/xlnt-community/xlnt/commit/f2d7bf494e5c52706843cf7eb9892821bffb0734
Published: 2026-02-19
Updated: 2026-02-19
Base Score: 1.7
Vector: CVSS2#AV:L/AC:L/Au:S/C:N/I:N/A:P
Severity: Low
Base Score: 3.3
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Severity: Low
Base Score: 4.8
Vector: 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
Severity: Medium
EPSS: 0.00013