CVE-2026-111127: Out-of-bounds Read (CVSS 6.1)

Description

catdoc through 0.95 contains an out-of-bounds read vulnerability in copy_unicode_string() in src/xlsparse.c that allows attackers to read past buffers via an unchecked string character count. Attackers can supply a crafted .xls file declaring 0xFFFF two-byte characters in LABEL, STRING, or SST records to disclose adjacent memory through xls2csv output or crash the process.

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CVSS v3.1 Score

6.1

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H

Weakness Type (CWE)

CWE-125 Out-of-bounds Read

References

Other References

https://github.com/vbwagner/catdoc https://github.com/vbwagner/catdoc/blob/38a2807d22ce1a08bc39b94e9072a9f8f52cd86f/src/xlsparse.c#L421-L520 https://hackmd.io/@haind-pwn/catdoc-xls-mulrk-endcol-and-string-count-oob-read https://www.vulncheck.com/advisories/catdoc-through-0.95-out-of-bounds-read-via-xls2csv-copy-unicode-string

Frequently Asked Questions

What is CVE-2026-111127? +

catdoc through 0.95 contains an out-of-bounds read vulnerability in copy_unicode_string() in src/xlsparse.c that allows attackers to read past buffers via an unchecked string character count. Attackers can supply a crafted .xls file declaring 0xFFFF two-byte characters in LABEL, STRING, or SST records to disclose adjacent memory through xls2csv output or crash the process. It has a CVSS v3.1 base score of 6.1 (MEDIUM).

How severe is CVE-2026-111127? +

CVE-2026-111127 has a CVSS v3.1 score of 6.1 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

How do I check if I'm vulnerable to CVE-2026-111127? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2026-111127