PT-2026-20595 · Xlnt · Xlnt

Oneafter · Published 2026-02-19 · Updated 2026-03-10 · CVE-2026-2703

Positive Technologies (AI Summary)

CVSS v3.1

5.5

Medium

Base vector

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

Name of the Vulnerable Software and Affected Versions xlnt versions up to 1.6.1

Description A flaw exists in the xlnt::detail::decode base64 function within the Encrypted XLSX File Parser component, specifically in the source/detail/cryptography/base64.cpp file. This can lead to an off-by-one error. Local access is required for exploitation. The exploit is publicly available.

Recommendations Apply the patch f2d7bf494e5c52706843cf7eb9892821bffb0734 to resolve this issue.

Exploit

Fix

Weakness Enumeration

CWE-189

CWE-193

Related Identifiers

CVE-2026-2703

Affected Products

Xlnt

References · 12

• 🔥 https://github.com/oneafter/0128/blob/main/xl1/repro · Exploit
• https://github.com/xlnt-community/xlnt/commit/f2d7bf494e5c52706843cf7eb9892821bffb0734 · Patch
• https://github.com/xlnt-community/xlnt/issues/137 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-2703 · Security Note
• https://osv.dev/vulnerability/CVE-2026-2703 · Vendor Advisory
• https://t.me/cveNotify/154977 · Telegram Post
• https://twitter.com/CVEnew/status/2025892084012445923 · Twitter Post
• https://vuldb.com/?id.346649 · Note
• https://github.com/xlnt-community/xlnt · Note
• https://vuldb.com/?submit.754377 · Note
• https://t.me/CVEtracker/45068 · Telegram Post
• https://vuldb.com/?ctiid.346649 · Note