What is the CVSS score of EUVD-2026-34336?

EUVD-2026-34336 has a CVSS 3.1 base score of 7.5 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. EPSS exploitation probability: 0.1%.

Which versions of Copilot Chat are affected by EUVD-2026-34336?

Copilot Chat within Microsoft Edge contains a vulnerability that allows unauthenticated attackers to leak sensitive user data.. A patch is available.

How to fix or mitigate EUVD-2026-34336?

Within 24 hours, verify patch availability through official Microsoft security advisories and confirm your standard Edge deployment mechanism (Windows Update, WSUS, or mobile device management). Within 7 days, deploy the patched Microsoft Edge version across all organizational endpoints. Within 30 days, validate complete patch deployment across all managed Edge installations and document remediation for compliance records.

Copilot Chat EUVD-2026-34336

| CVE-2026-47644 HIGH

Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') (CWE-74)

2026-06-04 microsoft

GHSA-6w62-wfvj-6pfp

Information Disclosure Microsoft Copilot Chat Microsoft Edge

7.5

CVSS 3.1 · NVD

Temporal: 5.7

Severity by source

NVD PRIMARY

7.5 HIGH

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CIRCL (temporal)

5.7 MEDIUM

cvss

vuln.today AI

7.5 HIGH

Network-reachable injection needing no auth or interaction (AV:N/AC:L/PR:N/UI:N); impact is confidentiality-only information disclosure, so C:H with I:N/A:N and unchanged scope.

3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Primary rating from NVD.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Lifecycle Timeline

Analysis Updated

Jul 23, 2026 - 07:30 vuln.today

v2 (cvss_changed)

Re-analysis Queued

Jul 23, 2026 - 07:22 vuln.today

cvss_changed

Severity Changed

Jul 23, 2026 - 07:22 NVD

MEDIUM HIGH

CVSS changed

Jul 23, 2026 - 07:22 NVD

6.5 (MEDIUM) 7.5 (HIGH)

Analysis Generated

Jun 04, 2026 - 23:03 vuln.today

CVE Published

Jun 04, 2026 - 22:00 nvd

MEDIUM 6.5

DescriptionNVD

Improper neutralization of special elements in output used by a downstream component ('injection') in Copilot Chat (Microsoft Edge) allows an unauthorized attacker to disclose information over a network.

AnalysisAI

Information disclosure in Copilot Chat within Microsoft Edge allows a remote, unauthenticated attacker to leak sensitive data by exploiting improper neutralization of special elements passed to a downstream component (an injection flaw). Microsoft has issued a fix, and the low EPSS score (0.08%) combined with a 'none' SSVC exploitation status indicates no public exploit identified at time of analysis. The CVSS 7.5 rating reflects a high confidentiality impact with no integrity or availability effect.

Technical ContextAI

The affected component is Copilot Chat, the AI assistant integrated into the Microsoft Edge browser (CPE cpe:2.3:a:microsoft:copilot_chat_(microsoft_edge)). The root cause is CWE-74, improper neutralization of special elements in output used by a downstream component - a general injection class in which attacker-influenced content is not sanitized before being handed to a consuming component that interprets it. In AI-assistant contexts this class commonly manifests as prompt- or content-injection where untrusted web/page content flows into the model's context or its rendered output, causing the assistant to emit or exfiltrate data the user did not intend to expose. The CVSS confidentiality-only impact (C:H/I:N/A:N) is consistent with an information-disclosure outcome rather than code execution or tampering.

RemediationAI

Patch available per vendor advisory: apply Microsoft's fix as documented in the MSRC update guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-47644. Because Copilot Chat is delivered through Microsoft Edge and its associated cloud service, ensure Microsoft Edge is updated to the latest version and that automatic updates are enabled so the service-side and client-side fixes are received; no discrete standalone patch version is published in the available data. As an interim compensating control where the update cannot be immediately applied, organizations can disable or restrict Copilot Chat in Edge via enterprise policy (e.g., the HubsSidebarEnabled / Copilot-related group policies), accepting the trade-off of losing the AI assistant feature for users. Additional advisory context is mirrored at https://nvd.nist.gov/vuln/detail/CVE-2026-47644 and https://vuldb.com/vuln/368416.