Undefined behavior in the WebRTC: Signaling component
Summary
| CVE | CVE-2026-4718 |
|---|---|
| State | PUBLISHED |
| Assigner | mozilla |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-03-24 13:16:07 UTC |
| Updated | 2026-04-13 15:17:43 UTC |
| Description | Undefined behavior in the WebRTC: Signaling component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9. |
Risk And Classification
Primary CVSS: v3.1 8.1 HIGH from [email protected]
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
EPSS: 0.000120000 probability, percentile 0.016540000 (date 2026-04-15)
Problem Types: CWE-758 | CWE-758 CWE-758 Reliance on Undefined, Unspecified, or Implementation-Defined Behavior
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Primary | 8.1 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N |
| 3.1 | ADP | DECLARED | 8.1 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N |
| 3.1 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | Secondary | 8.1 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
RequiredScope
UnchangedConfidentiality
HighIntegrity
HighAvailability
NoneCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
NVD Known Affected Configurations (CPE 2.3)
| Type | Vendor | Product | Version | Update | Edition | Language |
|---|---|---|---|---|---|---|
| Application | Mozilla | Firefox | All | All | All | All |
| Application | Mozilla | Firefox | All | All | All | All |
| Application | Mozilla | Thunderbird | All | All | All | All |
| Application | Mozilla | Thunderbird | All | All | All | All |
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Mozilla | Firefox | unaffected 140.9 140.* rpm | Not specified |
| CNA | Mozilla | Firefox | unaffected 149 * rpm | Not specified |
| CNA | Mozilla | Thunderbird | unaffected 140.9 140.* rpm | Not specified |
| CNA | Mozilla | Thunderbird | unaffected 149 * rpm | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| www.mozilla.org/security/advisories/mfsa2026-24 | [email protected] | www.mozilla.org | Vendor Advisory |
| www.mozilla.org/security/advisories/mfsa2026-23 | [email protected] | www.mozilla.org | Vendor Advisory |
| www.mozilla.org/security/advisories/mfsa2026-22 | [email protected] | www.mozilla.org | Vendor Advisory |
| www.mozilla.org/security/advisories/mfsa2026-20 | [email protected] | www.mozilla.org | Vendor Advisory |
| bugzilla.mozilla.org/show_bug.cgi | [email protected] | bugzilla.mozilla.org | Permissions Required |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Evyatar Ben Asher, Keane Lucas, Nicholas Carlini, Newton Cheng, Daniel Freeman, Alex Gaynor, and Joel Weinberger using Claude from Anthropic (en)
There are currently no legacy QID mappings associated with this CVE.