The maintainers of the official Model Context Protocol Python SDK disclosed a flaw that lets a malicious MCP server trick an application built on the SDK into handing over the OAuth credentials it uses to log in to a real service. Affected versions sent the client secret, authorization code, and PKCE proof key to an attacker-controlled token endpoint, because the SDK did not always verify where the authorization server was. Cycode, which reported it, exchanged the stolen material for a valid access token carrying the app's permissions, and noted the long-lived client secret keeps working until rotated. Fixes are in versions 1.30.0 and 2.2.0.
F5 released updates for a critical BIG-IP Access Policy Manager zero-day that it confirms is being exploited in remote code execution attacks. Tracked as CVE-2026-94127, the flaw affects instances configured as an OAuth Authorization Server, where a BIG-IP APM access policy and an OAuth profile sit on the same virtual server. Deployments using APM strictly as an OAuth client or resource server are not affected. F5 told customers to hunt for multiple OAuth authentication failures and suspicious commands followed by a TMM SIGABRT, and offered an iRule mitigation for those who cannot patch immediately. Shadowserver tracks over 14,700 exposed BIG-IP APM instances, and CISA added the flaw to its catalog.
A vulnerability in the workflow automation platform n8n could let an attacker log in as another user without their password. Tracked as CVE-2026-59208, the flaw sits in n8n's Enterprise token exchange feature, which lets embedded deployments avoid a second login by accepting tokens from partner identity providers. Because the code did not properly bind an identity to its issuer, a valid token from one issuer that carried the identifier of a user under a different issuer would log the attacker in as that user. n8n shipped a fix on June 24, and there is no evidence of exploitation. The bug was found by an AI penetration-testing agent.
Researchers at Miggo disclosed two access-control flaws in RabbitMQ, the widely used message broker, that have been present since early 2024. In the more serious one, an obsolete management endpoint had its authorization check hard-coded to always allow, so an unauthenticated attacker can leak the broker's confidential OAuth client secret in a single request, a direct path to full broker takeover where that secret is used. The second lets any logged-in user, even one with no assigned permissions, read other tenants' queue and exchange metadata, useful reconnaissance in shared environments. Both are fixed in updated releases, and the risk is sharpest where the management port is reachable from untrusted networks.
Kaspersky detailed Umbrij, a new tool from the ToddyCat espionage group that steals access to corporate Gmail without ever taking a password. Delivered on Windows through DLL side-loading via trusted signed programs, Umbrij copies the victim's already-signed-in browser profile, launches a hidden Chromium with remote debugging, and drives it through Google's OAuth flow while impersonating legitimate Google Workspace sync apps. Because the copied profile is already authenticated, Google issues an authorization code that is exchanged for an access token, giving the attackers API access to Gmail, Drive, Calendar, and more, and sidestepping both the password and multi-factor authentication. The technique shows how stealing OAuth tokens can quietly bypass account protections.
A new extortion group called Icarus stole Salesforce CRM data from multiple organizations by abusing Klue, a competitive-intelligence app that integrates with Salesforce. Attackers compromised Klue's backend through a dormant credential, pushed a malicious update that harvested customers' OAuth tokens, and used those tokens to run automated queries against Salesforce's API, exfiltrating contacts, sales communications, and account data over about a day. Salesforce has disabled the Klue Battlecards integration. It is the same OAuth-abuse playbook seen in the Salesloft Drift and Gainsight incidents, exploiting trusted third-party integrations that carry broad, lightly-monitored access. Researchers expect more such attacks through 2026.
Dark Reading reports that Kali365 - the phishing-as-a-service platform the FBI flagged for fueling Microsoft 365 attacks in April - is expanding its reach. Rather than stealing passwords, Kali365 captures OAuth access and refresh tokens by tricking victims into completing attacker-initiated Microsoft device-login requests, granting immediate mailbox access. The service generates branded lures impersonating Adobe, DocuSign, and SharePoint in many languages and sells in tiers from $250 for 30 days to $2,000 annually. Its continued growth signals that OAuth device-code consent phishing remains a high-yield technique, and that defenders should prioritize blocking device-code flows for non-mobile platforms and enforcing phishing-resistant MFA across Microsoft 365 tenants.
The FBI has issued a warning about Kali365, a phishing-as-a-service platform that fueled large Microsoft 365 attacks in April. Instead of stealing passwords, Kali365 customers trigger Microsoft device-login requests and trick victims into completing the authorization, capturing OAuth access and refresh tokens that grant immediate mailbox access. Arctic Wolf, which infiltrated the system, says Kali365 sells in three tiers from $250 for 30 days to $2,000 for the year and generates branded phishing lures impersonating Adobe, DocuSign, and SharePoint in dozens of languages. Threat actors set malicious inbox rules to suppress security notifications and extend dwell time.
The Tycoon 2FA phishing-as-a-service kit, which Microsoft, Europol, Cloudflare and others tried to dismantle in March 2026, is back and has switched tactics. Instead of relaying credentials and MFA codes through a fake login page, operators now send victims to Microsoft's legitimate device-login page at microsoft.com/devicelogin and ask them to enter a code from the lure email. That single consent grants the attacker OAuth tokens for the victim's Exchange Online, OneDrive, and SharePoint through Microsoft's own Authentication Broker app, so it looks normal in Entra logs. eSentire spotted the late-April campaign and published IoCs, including AS45102 (Alibaba Cloud) operator infrastructure.
Push Security disclosed ConsentFix v3, a new attack that lets criminals take over Microsoft 365 accounts even if the victim has MFA and phishing-resistant passkeys turned on. The trick: instead of stealing a password, the attacker tricks the user into pasting a Microsoft authorization URL into a phishing page during what looks like a routine login. That URL contains a one-time code that the attacker exchanges for permanent access tokens. v3 automates the whole attack with Cloudflare Pages phishing sites, Pipedream webhook automation, and tenant fingerprinting that customizes the lure to each target organization's branding.
TrustStrike Labs