AtRisk June 11, 2026 Vol. XXVI

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Microsoft June 2026 Patch Tuesday

Published: 2026-06-09

Last Updated: 2026-06-09 17:34:29 UTC

by Johannes Ullrich (Version: 1)

Microsoft today released patches for 204 vulnerabilities. 38 of these vulnerabilities are considered critical, and three have been disclosed before today. Six of the vulnerabilities affect Microsoft cloud solutions and do not require any user action. In addition, Microsoft incorporated 360 different vulnerabilities affecting Chromium into its Edge browser.

This is certainly a busier-than-usual patch Tuesday. In particular, the large number of patched Chromium/Edge vulnerabilities underscores the impact of AI tools on vulnerability discovery.

Some noteworthy vulnerabilities:

CVE-2026-49160: This vulnerability was made public a week ago. As implemented, the "HPACK" compression algorithm in HTTP/2 and HTTP/3 can lead to a "compression bomb" that consumes excessive resources. Many HTTP/2 implementations are vulnerable. Microsoft addressed this issue by adding a "MaxHeadersCount" registry setting that limits the amount of allocated resources.

- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-49160

CVE-2026-47291: Affecting the Microsoft web server engine http.sys, just like CVE-2026-49160, this vulnerability is rated critical and allows for remote code execution. The integer overflow requires an oversized request to trigger it. Microsoft recommends restricting the "MaxRequestBytes" to prevent exploitation until the patch can be rolled out.

- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-47291

CVE-2026-45648: A stack-based buffer overflow in Active Directory Domain Services. A successful attack requires authentication, and Microsoft considers exploit development as "unlikely".

- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45648

Microsoft fixed three different BitLocker security feature bypass vulnerabilities. One of the vulnerabilities was already publicly known. An "anonymous" researcher is credited with the discovery, but I assume it is one of the "Nightmare Eclipse" vulnerabilities.

Several critical vulnerabilities affect Microsoft Office, Outlook, and Word ...

Read the full entry: https://isc.sans.edu/diary/Microsoft+June+2026+Patch+Tuesday/33064/

How has use of framing protection security headers changed in the past 3 years?

Published: 2026-06-10

Last Updated: 2026-06-10 08:29:21 UTC

by Jan Kopriva (Version: 1)

Back in 2023, I wrote a diary (https://isc.sans.edu/diary/29698) discussing how commonly X-Frame-Options and CSP headers containing the frame-ancestors directive were used on 1 million most popular domains on the internet (based on the Tranco list), and how they were set. Given that three years have passed since then, I thought it might be interesting to repeat the analysis and see what – if anything – has changed in the meantime.

Before we get to the data, however, let’s briefly recap what the headers in question do and why they are important.

Both headers basically serve the same fundamental purpose – they inform a browser whether the content of a given web page may be embedded in an iframe or similar object on another web page. Without either of these headers in place, any web page may freely load any other web page in an iframe, which can be quite beneficial in some instances, but also provides a functionality that is commonly abused by phishing actors.

The most common abuse scenario is related to a generic framing attack, and leads to what is sometimes called an “overlay phishing”. It is based on an attacker creating a malicious page which loads a legitimate website (usually the official company website of the recipient of the phishing) in a full-screen iframe, then overlays a fake login prompt on top of it. The result is that the victim sees what may appear to be the real login page. Setting either X-Frame-Options or CSP with the frame-ancestors directive on the legitimate site effectively mitigates this approach, because the browser will refuse to load the page inside an iframe in the first place, and all that would be displayed would be a fake login form over a browser message informing the user that a page cannot be loaded (which should make the credential stealing form apper less than trustworthy to most people).

This is a good reason why these headers are worth implementing on any organization's web site, regardless of how prominent or otherwise “interesting” the organization might consider itself to be.

For completeness’ sake, it should be mentioned that although the two security headers serve a similar purpose, they are not exactly equal. The X-Frame-Options header is the older of the two mechanisms and, while functional, is relatively limited in what it can express. It supports three directives: DENY (the page may not be framed by anyone), SAMEORIGIN (the page may only be framed by pages on the same origin/domain), and ALLOW-FROM (the page may be framed by a specific origin/domain).

Although the header in general is still widely supported and does its job well, its ALLOW-FROM directive was never universally supported by all browsers and is now considered obsolete. More importantly, however, the X-Frame-Options header as a whole has been basically superseded by the Content Security Policy frame-ancestors directive.

The CSP frame-ancestors directive offers considerably more flexibility than X-Frame-Options. It supports the same basic use cases (frame-ancestors 'none' being equivalent to DENY, frame-ancestors 'self' being equivalent to SAMEORIGIN), but also enables some additional ones (such as supporting wildcard matching for subdomains etc.). Modern browsers therefore generally treat frame-ancestors as the authoritative directive, ignoring X-Frame-Options entirely when both are present. That said, X-Frame-Options remains relevant for legacy browser compatibility and – in practice – both headers can be sent simultaneously without any harm, which is what many HTTP servers actually do.

With this context in mind, let us look at how the use of these headers has evolved since 2023 ...

Read the full entry: https://isc.sans.edu/diary/How+has+use+of+framing+protection+security+headers+changed+in+the+past+3+years/33068/

TeamPCP Supply Chain Campaign: Activity Through 2026-06-07

Published: 2026-06-08

Last Updated: 2026-06-08 17:07:37 UTC

by Kenneth Hartman (Version: 1)

This diary continues the Internet Storm Center's tracking of the TeamPCP supply chain campaign, first documented in the SANS white paper When the Security Scanner Became the Weapon (https://www.sans.org/white-papers/when-security-scanner-became-weapon) and most recently in the handler diary Activity Through 2026-05-24 (https://isc.sans.edu/diary/33014). Since that update, the story moved into two new places: the United States government, which formally caught up to the campaign, and the wider population of attackers now wielding the Mini Shai-Hulud framework that TeamPCP open-sourced last month.

Bottom line up front

Two developments stand out since the last update. First, the federal response that prior coverage flagged as conspicuously absent arrived in a roughly 48-hour burst: on 2026-05-27 CISA added the campaign's primary tracking vulnerabilities to its Known Exploited Vulnerabilities catalog, and on 2026-05-28 it issued its first standalone advisory naming the Nx Console and GitHub repository compromises. Second, the leaked Mini Shai-Hulud framework produced its first significant in-the-wild npm wave: beginning 2026-06-01, a credential-stealing worm that Wiz named "Miasma" compromised dozens of @redhat-cloud-services packages, followed two days later by a "Phantom Gyp" variant that reached 57 more. Vendors trace the malware to the TeamPCP lineage but now explicitly caution that a copycat using the public toolkit cannot be ruled out. The affiliated extortion channels stayed frozen, so this period's activity was ecosystem-scale worming rather than named-victim extortion.

How this developed

The last update closed with two open questions: whether CISA would act on a campaign it had so far left out of the KEV catalog, and whether the framework TeamPCP published to GitHub would produce copycat attacks. Both resolved in the affirmative. CISA's KEV addition and standalone advisory closed the government-silence gap within roughly a day of each other. A week later, the Red Hat npm compromise demonstrated that the open-sourced code is now operational in other hands. The throughline is that the campaign has entered a phase where its tradecraft outlives any single operator: the same techniques, subverted build pipelines that emit validly signed artifacts and install-time credential theft, now arrive from attackers who may have no direct connection to TeamPCP at all.

What changed, by theme ...

Read the full entry: https://isc.sans.edu/diary/TeamPCP+Supply+Chain+Campaign+Activity+Through+20260607/33060/

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