CVE-2022-40958

MEDIUM

6.5

CVSS Score

Published: December 22, 2022 at 12:00 AM UTC

Updated: June 17, 2026 at 05:02 AM UTC

3 products affected across 1 vendorFirefoxThunderbirdFirefox ESR

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Severity

MEDIUM6.5

Exploit prediction

EPSS 1%

SSVC

No known exploit

Description

By injecting a cookie with certain special characters, an attacker on a shared subdomain which is not a secure context could set and thus overwrite cookies from a secure context, leading to session fixation and other attacks. This vulnerability affects Firefox ESR < 102.3, Thunderbird < 102.3, and Firefox < 105.

Affected

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

Firefox · Mozilla

95%

v < 105

Affected range stops below 105, so it looks safe — our inference, not a vendor statement

Affected range stops below 105.0, so it looks safe — our inference, not a vendor statement

Firefox ESR · Mozilla

95%

v < 102.3

Affected range stops below 102.3, so it looks safe — our inference, not a vendor statement

Thunderbird · Mozilla

95%

v < 102.3

Affected range stops below 102.3, 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 (4)

Issue TrackingPermissions Required

Source: [email protected]

https://bugzilla.mozilla.org/show_bug.cgi?id=1779993

Vendor Advisory

Source: [email protected]

https://www.mozilla.org/security/advisories/mfsa2022-40/

Vendor Advisory

Source: [email protected]

https://www.mozilla.org/security/advisories/mfsa2022-41/

Vendor Advisory

Source: [email protected]

https://www.mozilla.org/security/advisories/mfsa2022-42/

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

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

CVSS

6.5MEDIUMCISA-ADP

Attack Vector: NETWORK
Complexity: LOW
Privileges: NONE
User Interaction: REQUIRED
Scope: UNCHANGED
Confidentiality: NONE
Integrity: HIGH
Availability: NONE

Vector?

Quick Info

StatusMODIFIED

CWE

CWE-74

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