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Fencer Intel
low 3.3

CVE-2026-3463 json

xlnt-community xlnt Compound Document binary.hpp append heap-based overflow

published 8mo ago modified 4mo ago also EUVD-2026-9285

cvss
3.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 12%
public exploits
0
none known

Summary

A weakness has been identified in xlnt-community xlnt up to 1.6.1. Impacted is the function xlnt::detail::binary_writer::append of the file source/detail/binary.hpp of the component Compound Document Parser. This manipulation causes heap-based buffer overflow. The attack can only be executed locally. The exploit has been made available to the public and could be used for attacks. Patch name: 147. It is suggested to install a patch to address this issue.

Patch / fix

Is CVE-2026-3463 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
8mo ago

Exploit prediction

0.22% chance of exploitation in the next 30 days, higher than 12% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/oneafter/0128/blob/main/xl2/repro referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/xlnt-community/xlnt/issues/138 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 4.8 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
CNA 3.1 3.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:O/RC:C
CNA 3.0 3.3 CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:O/RC:C
CNA 2.0 1.7 AV:L/AC:L/Au:S/C:N/I:N/A:P/E:POC/RL:OF/RC:C
CNA 4.0 1.9 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
CNA 3.1 3.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA 2.0 1.7 AV:L/AC:L/Au:S/C:N/I:N/A:P

Affected products

  • xlnt-community xlnt

Classification

Weakness
  • CWE-122 Heap-based Buffer Overflow
  • CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.