CVE-2026-3463Public exploit

Process crash via unchecked sector-buffer append

Published Mar 3, 2026 · Updated Mar 3, 2026

Heap-based buffer overflow in xlnt 1.6.0 and 1.6.1 allows local users to crash a consuming process via a malformed encrypted XLSX file. While parsing the master sector allocation table, binary_writer::append writes 64 bytes immediately beyond a full 512-byte sector buffer instead of rejecting insufficient remaining capacity. Low-privileged local access is required to supply the file; published evidence demonstrates an out-of-bounds write and service interruption, not code execution.

CVSS severity7.8
High
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in xlnt 1.6.0 and 1.6.1 allows local users to crash a consuming process via a malformed encrypted XLSX file. While parsing the master sector allocation table, binary_writer::append writes 64 bytes immediately beyond a full 512-byte sector buffer instead of rejecting insufficient remaining capacity. Low-privileged local access is required to supply the file; published evidence demonstrates an out-of-bounds write and service interruption, not code execution.

The record

CVE
CVE-2026-3463
Published
Mar 3, 2026
Updated
Mar 3, 2026
Vendor
xlnt Community
Product
xlnt
Classifications
CWE-119, CWE-122
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 3, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 3, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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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
7.8NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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
1.7VulDBAV:L/AC:L/Au:S/C:N/I:N/A: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-122Heap-based Buffer Overflow

Public exploit references

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

Technologies

Your stack

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Your stack

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