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CVE-2023-4581

XLL file extensions were downloadable without warnings

MEDIUM
4.3
CVSS Score
Published: September 11, 2023 at 08:01 AM UTC
Updated: June 17, 2026 at 06:38 AM UTC
3 products affected across 1 vendorFirefoxThunderbirdFirefox ESR

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Severity
MEDIUM4.3
Exploit prediction
EPSS 0.6%
SSVC
No known exploit

Description

Excel `.xll` add-in files did not have a blocklist entry in Firefox's executable blocklist which allowed them to be downloaded without any warning of their potential harm. This vulnerability affects Firefox < 117, Firefox ESR < 102.15, Firefox ESR < 115.2, Thunderbird < 102.15, and Thunderbird < 115.2.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Firefox· Mozilla
95%
v < 117v < 117.0115.0 ≤ v < 115.2
Affected range stops below 115.2, so it looks safe — our inference, not a vendor statement
Affected range stops below 117, so it looks safe — our inference, not a vendor statement
Affected range stops below 117.0, so it looks safe — our inference, not a vendor statement
Firefox ESR· Mozilla
95%
v < 102.15v < 115.2
Affected range stops below 102.15, so it looks safe — our inference, not a vendor statement
Affected range stops below 115.2, so it looks safe — our inference, not a vendor statement
Thunderbird· Mozilla
95%
v < 102.15v < 115.2
Affected range stops below 102.15, so it looks safe — our inference, not a vendor statement
Affected range stops below 115.2, so it looks safe — our inference, not a vendor statement

References (6)

Issue TrackingPermissions Required
Source: [email protected]
https://bugzilla.mozilla.org/show_bug.cgi?id=1843758
Vendor Advisory
Source: [email protected]
https://www.mozilla.org/security/advisories/mfsa2023-34/
Vendor Advisory
Source: [email protected]
https://www.mozilla.org/security/advisories/mfsa2023-35/
Vendor Advisory
Source: [email protected]
https://www.mozilla.org/security/advisories/mfsa2023-36/
Vendor Advisory
Source: [email protected]
https://www.mozilla.org/security/advisories/mfsa2023-37/
Vendor Advisory
Source: [email protected]
https://www.mozilla.org/security/advisories/mfsa2023-38/

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

4.3MEDIUM[email protected]
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
NVD-CWE-noinfo

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