Loading story…
Microsoft disclosed CVE-2026-50517, a critical remote code execution flaw in Microsoft 365 Copilot caused by deserialization of untrusted data (CWE-502). The vulnerability allows an authenticated attacker with low privileges to execute code over the network without user interaction, and carries a CVSS 3.1 score of 9.9 with the vector AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H, indicating high impact across confidentiality, integrity, and availability with changed scope.
The issue affects the hosted Microsoft 365 Copilot service, and Microsoft remediated it on the service side rather than through a customer-installed patch. Reporting indicated all versions of M365 Copilot were affected, while no active exploitation had been publicly reported at the time of disclosure. Organizations were advised to confirm tenant coverage, review Copilot permissions and access, enable auditing, and monitor for unusual Copilot-related activity.
Mallory correlates global threat intelligence with your attack surface — know if you’re exposed before adversaries strike.
2 events from the most recent confirmed update back to the earliest known activity.
Microsoft remediated CVE-2026-50517 on the managed M365 Copilot service side, meaning customers did not need to apply a local patch. The reporting also stated that all versions of Microsoft 365 Copilot were affected and that no active exploitation had been reported at the time of publication.
Microsoft published a vulnerability reference for CVE-2026-50517 in the MSRC update guide on 2026-07-24. The issue affects Microsoft 365 Copilot and is described as a deserialization of untrusted data flaw that can allow authenticated remote code execution over a network.
Vulnerabilities, threat actors, malware, products, organizations, and breaches Mallory has linked to this story.
2 references tracked. Mallory keeps watching after this page renders.
Map indicators from this story to your assets and identify affected systems in minutes.
Every observed campaign, victim, and pivot linked to actors named in this story.
Malware, exploits, and IOCs connected to the activity described here.
YARA, Sigma, and Snort rules deployed to your SIEM as soon as they’re published.
Get matching new stories delivered to your team as they break — not the next morning.
Ask questions about this story and take action on the answers.
Other stories Mallory is tracking that overlap on entities, sources, or topic labels.
Microsoft disclosed **CVE-2026-48561**, a critical remote code execution flaw in **Microsoft Copilot** caused by **CWE-77 command injection**. The vulnerability carries a **CVSS 3.1 score of 9.6** and can be exploited remotely without privileges, though **user interaction is required**. Microsoft said the issue was **not publicly disclosed** and **not exploited** at the time of publication, and rated exploitation as **less likely**. According to the advisory, an attacker could host a malicious website that causes **Microsoft Edge for Android** to automatically send crafted prompts to Copilot, potentially triggering unintended actions such as accessing or modifying data. Microsoft also warned that successful exploitation could involve a **scope change**, including traversal from a **low-privilege Hyper-V guest** to code execution on the **Hyper-V host**. A security update was available when the advisory was published, and Microsoft credited **Ofek Levin of Enclave** with reporting the bug.
Jul 14, 2026
Microsoft disclosed a set of security flaws affecting cloud and AI services, including **Microsoft 365 Copilot**, **Microsoft Copilot**, **Microsoft 365 Copilot BizChat**, **Azure DevOps**, **Azure Cloud Shell**, **Azure Data Factory**, **Microsoft Bing**, and **Microsoft Bing Images**. The issues span **information disclosure**, **elevation of privilege**, **tampering**, and **remote code execution**, with published identifiers including `CVE-2026-24299`, `CVE-2026-26136`, `CVE-2026-26137`, `CVE-2026-23658`, `CVE-2026-32169`, `CVE-2026-23659`, `CVE-2026-26120`, and `CVE-2026-32191`. Germany's dCERT separately highlighted multiple vulnerabilities in **Microsoft 365 Copilot**, underscoring enterprise concern around AI-assisted productivity platforms. The most severe issue in the group is **`CVE-2026-32191`**, a **critical remote code execution** flaw in **Microsoft Bing Images**. Public reporting tied the bug to **OS command injection** caused by improper neutralization of special elements in a command, potentially allowing an unauthenticated attacker to execute code over a network. Additional Bing exposure was tracked as **`CVE-2026-26120`**, a tampering vulnerability, while the Copilot-related flaws included both **information disclosure** and **privilege escalation**, indicating risk to data confidentiality and tenant-level access boundaries across Microsoft's hosted services.
Jul 24, 2026
Varonis Threat Labs disclosed **SearchLeak**, a critical exploit chain in Microsoft 365 Copilot Enterprise Search that could let an attacker steal sensitive enterprise data after a user clicked a single trusted `microsoft.com` link. Microsoft tracked the issue as **`CVE-2026-42824`** and remediated it on the backend. According to the researchers, the attack could expose data available through the victim’s Microsoft Graph permissions, including emails, calendar entries, meeting notes, SharePoint content, OneDrive files, and potentially MFA-related messages, though no in-the-wild exploitation was reported. The technique chained three weaknesses: **parameter-to-prompt injection** through the Copilot Search `q` parameter, an **HTML streaming race condition** that allowed an injected image tag to render before sanitization, and abuse of a **Bing allowlist** in Content Security Policy to exfiltrate the retrieved data through Bing’s server-side image fetch behavior. Researchers said the attack required no plugins, elevated privileges, or second user interaction, highlighting how AI prompt injection can revive older web security flaws in enterprise platforms. Microsoft rated the flaw critical, while public severity scoring differed across sources, and defenders were advised to watch for suspicious Copilot Search URLs containing encoded or HTML payloads and unusual Bing image endpoint traffic.
Jun 29, 2026