CVE-2021-23995
HIGH
8.8
CVSS Score
Published: June 24, 2021 at 01:26 PM UTC
Updated: June 17, 2026 at 03:39 AM UTC
3 products affected across 1 vendorFirefoxThunderbirdFirefox ESR
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Severity
HIGH8.8
Exploit prediction
EPSS 1%
Description
When Responsive Design Mode was enabled, it used references to objects that were previously freed. We presume that with enough effort this could have been exploited to run arbitrary code. This vulnerability affects Firefox ESR < 78.10, Thunderbird < 78.10, and Firefox < 88.
Affected
Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.
v < 88
Affected range stops below 88, so it looks safe — our inference, not a vendor statement
Affected range stops below 88.0, so it looks safe — our inference, not a vendor statement
v < 78.10
Affected range stops below 78.10, so it looks safe — our inference, not a vendor statement
v < 78.10
Affected range stops below 78.10, 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=1699835x_refsource_MISCRelease NotesVendor Advisory
Source: [email protected]
https://www.mozilla.org/security/advisories/mfsa2021-14/x_refsource_MISCRelease NotesVendor Advisory
Source: [email protected]
https://www.mozilla.org/security/advisories/mfsa2021-15/x_refsource_MISCRelease NotesVendor Advisory
Source: [email protected]
https://www.mozilla.org/security/advisories/mfsa2021-16/CVSS
- Attack Vector
- NETWORK
- Complexity
- LOW
- Privileges
- NONE
- User Interaction
- REQUIRED
- Scope
- UNCHANGED
- Confidentiality
- HIGH
- Integrity
- HIGH
- Availability
- HIGH
Vector?
Quick Info
StatusMODIFIED
CWE
CWE-672
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