CVE-2026-40359

high

Published 2026-05-12 · Modified 2026-05-19

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CVSS v3

7.8

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

CVSS v4 NEW

—

not yet in upstream

VIR risk

7.8

Description

<p>Use after free in Microsoft Office Excel allows an unauthorized attacker to execute code locally.</p>

Predictions

Exploit likelihood

75%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.

✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here with source_tier=community-verified.

OS impact

OS	Version	Status	Fixed in
windows		affected

Application impact

Vendor	Product	Versions	Fixed
microsoft	365_apps	`-`
microsoft	excel	`2016`
microsoft	office	`2019`
microsoft	office_long_term_servicing_channel	`2021`
microsoft	office_long_term_servicing_channel	`2024`
microsoft	office_online_server	`{"endExcluding":"16.0.10417.20128"}`	`16.0.10417.20128`

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40359

CWEs

CWE-416

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.