CVE-2021-25631 | denylist of executable filename extensions possible to bypass under windows

Exp

In the LibreOffice 7-1 series in versions prior to 7.1.2, and in the 7-0 series in versions prior to 7.0.5, the denylist can be circumvented by manipulating the link so it doesn't match the denylist but results in ShellExecute attempting to launch an executable type.

Published: 2021-05-03 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-25631 is rated High Exploit Risk (80.5/100): CVSS High severity, with medium exploitation likelihood (EPSS 4.17%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2021-25631

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-25631

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-17 5.27% 4.17% -1.10%
2 2026-06-15 1.32% 5.27% +3.95%
3 2026-05-29 — 1.32% —

Full EPSS history (20 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-25631

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.8 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.9 [email protected]
9.3 2.0 HIGH
AV:N/AC:M/Au:N/C:C/I:C/A:C Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:C)
Complete confidentiality impact.
Integrity impact (I:C)
Complete integrity impact.
Availability impact (A:C)
Complete availability impact.
 8.6 10.0 [email protected]

Weakness enumeration for CVE-2021-25631

OS Trackers for CVE-2021-25631

vendor priority summary link
alpine high CVE-2021-25631: 1 source package rows (libreoffice); 7 state rows across 7 repos (3.17-community, 3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 7, open 0. https://security.alpinelinux.org/vuln/CVE-2021-25631
debian unimportant CVE-2021-25631 unimportant priority: Debian including 1 source packages (libreoffice), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-25631
suse high — https://www.suse.com/security/cve/CVE-2021-25631/
ubuntu low CVE-2021-25631 low priority: Ubuntu including 1 source packages (libreoffice), 9 status rows across 9 suites (bionic, focal, groovy, hirsute, impish, jammy, trusty, upstream, xenial): not-affected 6, ignored 2, DNE 1. https://ubuntu.com/security/CVE-2021-25631

Affected software / configurations for CVE-2021-25631

Vendor Product Version Raw CPE
libreoffice libreoffice >= 7.0.0, < 7.0.5 cpe:2.3:a:libreoffice:libreoffice:*:*:*:*:*:*:*:*
libreoffice libreoffice >= 7.1.0, < 7.1.2 cpe:2.3:a:libreoffice:libreoffice:*:*:*:*:*:*:*:*

References for CVE-2021-25631

cvelogic Threat Intelligence