CVE-2026-3663Public exploit

Application crash via unchecked sector-chain traversal

Published Mar 7, 2026 · Updated Mar 7, 2026

Out-of-bounds read in xlnt 1.6.0 through 1.6.1 allows local users to crash applications that parse a crafted encrypted XLSX file. The xlnt::detail::compound_document_istreambuf::xsgetn function advances beyond the OLE stream's sector-chain vector and reads the next sector identifier outside the allocation. Exploitation requires local access and workbook loading through software linked with xlnt; the demonstrated consequence is a process crash.

CVSS severity3.3
Low
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Out-of-bounds read in xlnt 1.6.0 through 1.6.1 allows local users to crash applications that parse a crafted encrypted XLSX file. The xlnt::detail::compound_document_istreambuf::xsgetn function advances beyond the OLE stream's sector-chain vector and reads the next sector identifier outside the allocation. Exploitation requires local access and workbook loading through software linked with xlnt; the demonstrated consequence is a process crash.

The record

CVE
CVE-2026-3663
Published
Mar 7, 2026
Updated
Mar 7, 2026
Vendor
xlnt Community
Product
xlnt
Classifications
CWE-119, CWE-125, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 7, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 7, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.6.0
  2. Affected versionversion=1.6.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

xlnt Community · xlntversion=1.6.0; version=1.6.1

Published CVSS scores

3.3VulDBCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
1.7VulDBAV:L/AC:L/Au:S/C:N/I:N/A:P
1.9VulDBCVSS: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

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
CWE-125Out-of-bounds Read
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo