PT-2026-23864 · Xlnt · Xlnt

Oneafter · Published 2026-03-07 · Updated 2026-03-10 · CVE-2026-3665

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 xlnt that could lead to a null pointer dereference. The issue is located in the xlnt::detail::xlsx consumer::read office document function within the source/detail/serialization/xlsx consumer.cpp file of the XLSX File Parser component. Exploitation requires local access. The exploit is publicly available.

Recommendations Versions prior to 1.6.1 should be updated. As a temporary workaround, consider restricting access to the vulnerable function xlnt::detail::xlsx consumer::read office document until a patch is available.

Exploit

Fix

NULL Pointer Dereference

Improper Resource Release

Weakness Enumeration

CWE-476

CWE-404

Related Identifiers

CVE-2026-3665

Affected Products

Xlnt

References · 12

• 🔥 https://github.com/oneafter/0128/blob/main/xl4/repro · Exploit
• https://github.com/xlnt-community/xlnt/issues/140 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-3665 · Security Note
• https://osv.dev/vulnerability/CVE-2026-3665 · Vendor Advisory
• https://twitter.com/VulmonFeeds/status/2030332153020506122 · Twitter Post
• https://vuldb.com/?ctiid.349554 · Note
• https://vuldb.com/?id.349554 · Note
• https://t.me/CVEtracker/46735 · Telegram Post
• https://t.me/cveNotify/154984 · Telegram Post
• https://github.com/xlnt-community/xlnt · Note
• https://vuldb.com/?submit.764647 · Note
• https://twitter.com/CVEnew/status/2030339298348961864 · Twitter Post