CVE-2026-3663: A vulnerability was found in xlnt-community xlnt up to 1.6.1

Q: How do I fix CVE-2026-3663?

xlnt: upgrade to newer than 1.6.1. Exact commands for each OS are on this page.

Q: Is CVE-2026-3663 being exploited?

CVE-2026-3663 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-3663 affect?

CVE-2026-3663 affects xlnt. Severity is low (CVSS 3.3). 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.

Q: How urgent is CVE-2026-3663?

Priority 18/100. Public exploit reference

Routine

LOW 3.3UPGRADE

CVE-2026-3663 is a low-severity flaw (CVSS 3.3) affecting xlnt. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	3.3 (Low)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.2% (top 93%)
CISA exploited list	No
Weakness	CWE-119, CWE-125
Published	2026-03-07
Last modified	2026-06-17

Publisher (CNA): VulDB · Vendor: xlnt-community

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-03-07 15:15 UTCPublished CVE record published
2026-06-17 10:43 UTCUpdated Record last modified

xlnt-community xlnt UPGRADE

Affected: <= 1.6.1

Fixed in: newer than 1.6.1

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy xlnt || rpm -q xlnt || xlnt --version

2. UPGRADE to newer than 1.6.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade xlnt

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade xlnt

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-3663?

xlnt: upgrade to newer than 1.6.1. Exact commands for each OS are on this page.

Is CVE-2026-3663 being exploited?

CVE-2026-3663 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-3663 affect?

CVE-2026-3663 affects xlnt. Severity is low (CVSS 3.3). 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.

How urgent is CVE-2026-3663?

Priority 18/100. Public exploit reference

Related CVEs

CVE-2026-3665 LOW 3.3 UPGRADE A vulnerability was identified in xlnt-community xlnt up to 1.6.1
CVE-2026-3664 LOW 3.3 UPGRADE A vulnerability was determined in xlnt-community xlnt up to 1.6.1
CVE-2026-3463 LOW 3.3 UPGRADE A weakness has been identified in xlnt-community xlnt up to 1.6.1

References

← Back to latest CVEs