vulntracker.iovulntracker.io
© 2026 vulntracker.io

CVE-2021-23968

MEDIUM
4.3
CVSS Score
Published: February 26, 2021 at 01:59 AM UTC
Updated: June 17, 2026 at 03:39 AM UTC
4 products affected across 2 vendorsDebian LinuxFirefoxThunderbird

Using Firefox by Mozilla?

Get instant alerts when new vulnerabilities affect Firefox - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Start FreeSign In
Severity
MEDIUM4.3
Exploit prediction
EPSS 1%

Description

If Content Security Policy blocked frame navigation, the full destination of a redirect served in the frame was reported in the violation report; as opposed to the original frame URI. This could be used to leak sensitive information contained in such URIs. This vulnerability affects Firefox < 86, Thunderbird < 78.8, and Firefox ESR < 78.8.

Affected

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

Debian Linux· Debiandrupal
95%
10.09.0
Firefox· Mozilla
95%
v < 86
Affected range stops below 86, so it looks safe — our inference, not a vendor statement
Affected range stops below 86.0, so it looks safe — our inference, not a vendor statement
Firefox ESR· Mozilla
95%
v < 78.8
Affected range stops below 78.8, so it looks safe — our inference, not a vendor statement
Thunderbird· Mozilla
95%
v < 78.8
Affected range stops below 78.8, so it looks safe — our inference, not a vendor statement

References (8)

x_refsource_MISCIssue TrackingPermissions RequiredVendor Advisory
Source: [email protected]
https://bugzilla.mozilla.org/show_bug.cgi?id=1687342
Mailing Listx_refsource_MLISTThird Party Advisory
Source: [email protected]
https://lists.debian.org/debian-lts-announce/2021/03/msg00000.html
Vendor Advisoryx_refsource_GENTOOThird Party Advisory
Source: [email protected]
https://security.gentoo.org/glsa/202104-09
Vendor Advisoryx_refsource_GENTOOThird Party Advisory
Source: [email protected]
https://security.gentoo.org/glsa/202104-10
Vendor Advisoryx_refsource_DEBIANThird Party Advisory
Source: [email protected]
https://www.debian.org/security/2021/dsa-4866
x_refsource_MISCRelease NotesVendor Advisory
Source: [email protected]
https://www.mozilla.org/security/advisories/mfsa2021-07/
x_refsource_MISCRelease NotesVendor Advisory
Source: [email protected]
https://www.mozilla.org/security/advisories/mfsa2021-08/
x_refsource_MISCRelease NotesVendor Advisory
Source: [email protected]
https://www.mozilla.org/security/advisories/mfsa2021-09/

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
CWE-209

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Create accountSign in
Free plan, no card