xlnt-community xlnt up to 1.6.1 XLSX File Parser compound_document.cpp xsgetn out-of-bounds

HistoryDiffrelatejsonxmlCTI

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
4.5	$0-$5k	0.00

Summaryinfo

A vulnerability classified as problematic was found in xlnt-community xlnt up to 1.6.1. Impacted is the function xlnt::detail::compound_document_istreambuf::xsgetn of the file source/detail/cryptography/compound_document.cpp of the component XLSX File Parser. Executing a manipulation can lead to out-of-bounds. This vulnerability is tracked as CVE-2026-3663. The attack is restricted to local execution. Moreover, an exploit is present. Applying a patch is advised to resolve this issue.

Detailsinfo

A vulnerability classified as problematic was found in xlnt-community xlnt up to 1.6.1. This vulnerability affects the function xlnt::detail::compound_document_istreambuf::xsgetn of the file source/detail/cryptography/compound_document.cpp of the component XLSX File Parser. The manipulation with an unknown input leads to a out-of-bounds vulnerability. The CWE definition for the vulnerability is CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. As an impact it is known to affect availability.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-3663. The exploitation appears to be easy. The attack needs to be approached locally. Technical details and also a public exploit are known.

It is possible to download the exploit at github.com. It is declared as proof-of-concept.

Applying the patch 147 is able to eliminate this problem. The bugfix is ready for download at github.com.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-10155). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Vendor

xlnt-community

Name

xlnt

Version

Website

Product: https://github.com/xlnt-community/xlnt/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 4.6
VulDB Meta Temp Score: 4.5

VulDB Base Score: 3.3
VulDB Temp Score: 3.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 7.1
NVD Vector: 🔒

CNA Base Score: 3.3
CNA Vector: 🔒

CVSSv2info

AV	AC	Au	C	I	A
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💳	💳	💳	💳	💳	💳
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Out-of-bounds
CWE: CWE-125 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Access: Public
Status: Proof-of-Concept
Download: 🔒

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔒

Patch: 147

Timelineinfo

03/06/2026 Advisory disclosed
03/06/2026 +0 days VulDB entry created
03/12/2026 +6 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: 139
Status: Confirmed

CVE: CVE-2026-3663 (🔒)
GCVE (CVE): GCVE-0-2026-3663
GCVE (VulDB): GCVE-100-349552
EUVD: 🔒
scip Labs: https://www.scip.ch/en/?labs.20161013

Entryinfo

Created: 03/06/2026 21:39
Updated: 03/12/2026 14:17
Changes: 03/06/2026 21:39 (60), 03/07/2026 22:24 (1), 03/08/2026 15:36 (30), 03/12/2026 14:17 (12)
Complete: 🔍
Submitter: Oneafter
Cache ID: 216:22D:103

Submitinfo

Accepted

Submit #764644: xlnt-community xlnt commit bceb706 and before Heap-based Buffer Overflow (by Oneafter)

VulDB is the best source for vulnerability data and more expert information about this specific topic.