CVE-2026-2703 xlnt-community xlnt Encrypted XLSX File base64.cpp decode_base64 off-by-one
An off-by-one error in the base64 decoder of the xlnt library allows attackers to cause memory corruption via crafted encrypted XLSX files.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-2703?
CVE-2026-2703 is a medium-severity vulnerability in xlnt-community xlnt, published on 19 Feb 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-2703?
It affects 1 product.
Products include Xlnt-Community Xlnt.
How do I fix CVE-2026-2703?
No fix has been published for CVE-2026-2703 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-2703 being exploited?
There is no known exploitation of CVE-2026-2703 in the wild and no public exploit code.
Other vulnerabilities in xlnt-community xlnt
- CVE-2026-3663 xlnt-community xlnt XLSX File compound_document.cpp xsgetn out-of-bounds
- CVE-2026-3664 xlnt-community xlnt Encrypted XLSX File compound_document.cpp read_directory out-of-bounds
- CVE-2026-3665 xlnt-community xlnt XLSX File xlsx_consumer.cpp read_office_document null pointer dereference
- CVE-2026-3463 xlnt-community xlnt Compound Document binary.hpp append heap-based overflow
Sources
Also known as GHSA-pf2p-f275-6cmx.