CVE-2021-23953
MEDIUM
4.3
CVSS Score
Published: February 26, 2021 at 02:11 AM UTC
Updated: June 17, 2026 at 03:39 AM UTC
3 products affected across 1 vendorFirefoxThunderbirdFirefox ESR
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Severity
MEDIUM4.3
Exploit prediction
EPSS 1%
Description
If a user clicked into a specifically crafted PDF, the PDF reader could be confused into leaking cross-origin information, when said information is served as chunked data. This vulnerability affects Firefox < 85, Thunderbird < 78.7, and Firefox ESR < 78.7.
Affected
Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.
v < 85
Affected range stops below 85, so it looks safe — our inference, not a vendor statement
Affected range stops below 85.0, so it looks safe — our inference, not a vendor statement
v < 78.7
Affected range stops below 78.7, so it looks safe — our inference, not a vendor statement
v < 78.7
Affected range stops below 78.7, so it looks safe — our inference, not a vendor statement
Remediation
No guide yetNo remediation guidance has been written for this CVE yet. What the record does show:
References (4)
x_refsource_MISCIssue TrackingPermissions RequiredVendor Advisory
Source: [email protected]
https://bugzilla.mozilla.org/show_bug.cgi?id=1683940x_refsource_MISCRelease NotesVendor Advisory
Source: [email protected]
https://www.mozilla.org/security/advisories/mfsa2021-03/x_refsource_MISCRelease NotesVendor Advisory
Source: [email protected]
https://www.mozilla.org/security/advisories/mfsa2021-04/x_refsource_MISCRelease NotesVendor Advisory
Source: [email protected]
https://www.mozilla.org/security/advisories/mfsa2021-05/CVSS
- 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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