EUVD-2026-78506
GHSA-23hv-3g2f-xqvg
Severity by source
AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Network-delivered media parsing with no privileges needed, but required victim interaction and non-automatable per SSVC keep UI:R while impact is total within the client.
Primary rating from Vendor (mozilla).
CVSS VectorVendor: mozilla
Lifecycle Timeline
4DescriptionCVE.org
Privilege escalation due to incorrect boundary conditions in the Audio/Video component. This vulnerability was fixed in Firefox 156 and Firefox ESR 153.3.
AnalysisAI
A memory-safety flaw in Firefox's Audio/Video component - a classic out-of-bounds write/overflow class issue caused by incorrect boundary checking - lets an attacker who convinces a user to open a crafted page or media file corrupt memory and escalate privileges to the level the browser process runs at. The issue affects Firefox branches prior to 156 and Firefox ESR prior to 153.3, and is reachable without authentication but requires user interaction. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires user interaction per CVSS UI:R - the victim must load attacker-controlled content that causes Firefox's media decoder to parse a crafted Audio/Video stream, either by visiting a malicious or compromised page or by opening a weaponized media file. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 vector is CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H (8.8 High): network-deliverable, low complexity, no privileges or authentication needed, but gated by required user interaction, with total confidentiality, integrity and availability impact inside the vulnerable component. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Upgrade to Firefox 156 or Firefox ESR 153.3 as released by Mozilla - the fix versions are stated in the CVE record and detailed in MFSA2026-90 (https://www.mozilla.org/security/advisories/mfsa2026-90/) and MFSA2026-93 (https://www.mozilla.org/security/advisories/mfsa2026-93/). … Detailed patch versions, workarounds, and compensating controls in full report. |
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External POC / Exploit Code
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