How serious is CVE-2026-3663?

This vulnerability has a CVSS score of 4.8 out of 10, classified as MEDIUM severity. Proof-of-concept exploit code is publicly available, making this an active threat.

Is there exploit code available for CVE-2026-3663?

Yes, proof-of-concept exploit code for CVE-2026-3663 is publicly available on GitHub and security research platforms. This increases the risk of active exploitation.

Which products are affected by CVE-2026-3663?

CVE-2026-3663 affects xlnt-community xlnt. Check the full CVE details for specific version information.

How do I fix CVE-2026-3663?

To remediate CVE-2026-3663, check for security patches from xlnt-community. Apply all available updates and security patches. If no patch is available, implement recommended workarounds or security controls to mitigate the risk.

CVE-2026-3663

Medium

|4.8

Exploit Available

Plain English Summary

AI-powered analysis for quick understanding

This vulnerability allows an attacker with local access to read beyond the intended limits of memory in the xlnt XLSX file parser, potentially exposing sensitive information. It is important to apply the provided patch to fix this issue, as the exploit has already been made public.

Technical Description

A vulnerability was found in xlnt-community xlnt up to 1.6.1. This issue affects the function xlnt::detail::compound_document_istreambuf::xsgetn of the file source/detail/cryptography/compound_document.cpp of the component XLSX File Parser. Performing a manipulation results in out-of-bounds read. The attack is only possible with local access. The exploit has been made public and could be used. The patch is named 147. It is recommended to apply a patch to fix this issue.

CVSS Vector Analysis

Attack VectorLocal

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

Confidentiality ImpactHigh

Integrity ImpactHigh

Availability ImpactHigh

ScopeChanged

Vector String

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/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Exploit Resources

Search for proof-of-concept code and exploit modules

GitHub Search Exploit-DB Nuclei Templates Metasploit Vulners

Official References

NIST NVD

Est. Bounty

$638($500-$1K)

Vendor Response

Grade APatched in 3 days

Quick Information

Published

Mar 7, 2026

about 1 month ago

Last Modified

Mar 10, 2026

28 days ago

Vendor

xlnt-community

Product

xlnt

Related Vulnerabilities

CVE-2026-3665Medium

This vulnerability allows an attacker to crash the xlnt application by causing it to access a part of memory that doesn't exist, leading to a program failure. The attacker must have local access to the system to exploit this issue, and there are publicly available methods to do so.

CVE-2026-3664Medium

This vulnerability allows an attacker to read sensitive data from memory by manipulating how the software processes encrypted XLSX files. However, the attack can only be carried out locally, meaning the attacker needs access to the system where the software is running.