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CVE-2023-6205

MEDIUM
6.5
CVSS Score
Published: November 21, 2023 at 02:28 PM UTC
Updated: June 17, 2026 at 06:50 AM UTC
4 products affected across 2 vendorsDebian LinuxFirefoxThunderbird

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.9%
SSVC
No known exploit

Description

It was possible to cause the use of a MessagePort after it had already been freed, which could potentially have led to an exploitable crash. This vulnerability affects Firefox < 120, Firefox ESR < 115.5.0, and Thunderbird < 115.5.

Affected

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

Debian Linux· Debiandrupal
95%
10.011.012.0
Firefox· Mozilla
95%
v < 120
Affected range stops below 120, so it looks safe — our inference, not a vendor statement
Affected range stops below 120.0, so it looks safe — our inference, not a vendor statement
Firefox ESR· Mozilla
95%
v < 115.5.0
Affected range stops below 115.5.0, so it looks safe — our inference, not a vendor statement
Thunderbird· Mozilla
95%
v < 115.5
Affected range stops below 115.5, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (7)

Issue TrackingPermissions Required
Source: [email protected]
https://bugzilla.mozilla.org/show_bug.cgi?id=1854076
Mailing List
Source: [email protected]
https://lists.debian.org/debian-lts-announce/2023/11/msg00017.html
Source: [email protected]
https://lists.debian.org/debian-lts-announce/2023/11/msg00030.html
Third Party Advisory
Source: [email protected]
https://www.debian.org/security/2023/dsa-5561
Release NotesVendor Advisory
Source: [email protected]
https://www.mozilla.org/security/advisories/mfsa2023-49/
Release NotesVendor Advisory
Source: [email protected]
https://www.mozilla.org/security/advisories/mfsa2023-50/
Release NotesVendor Advisory
Source: [email protected]
https://www.mozilla.org/security/advisories/mfsa2023-52/

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

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

CVSS

6.5MEDIUM[email protected]
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-416

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