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With the advent of a potential Dolby Unified Decoder RCE exploit, it seemed prudent to see what kind of Linux kernel drivers might be accessible from the resulting userland context, the mediacodec context. As per the AOSP documentation , the mediacodec SELinux context is intended to be a constrained (a.k.a sandboxed) context where non-secure software decoders are utilized. Nevertheless, using my DriverCartographer tool, I discovered an interesting device driver, /dev/bigwave that was accessible from the mediacodec SELinux context. BigWave is hardware present on the Pixel SOC that accelerates AV1 decoding tasks, which explains why it is accessible from the mediacodec context. As previous research has copiously affirmed , Android drivers for hardware devices are prime places to find powerful local privilege escalation bugs. The BigWave driver was no exception - across a couple hours of auditing the code, I discovered three separate bugs, including one that was powerful enough to escape the mediacodec sandbox and get kernel arbitrary read/write on the Pixel 9. The (Very Short) Bug Hunt The first bug I found was a duplicate that was originally reported in February of 2024 but remained unfixed at the time of re-discovery in June of 2025, over a year later, despite the bugfix being a transposition of two lines of code. The second bug presented a really fascinating bug-class that is analogous to the double-free kmalloc exploitation primitive - but with a different linked list entirely. However it was the third bug I discovered that created the nicest exploitation primitive. Fixes were made available for all three bugs on January 5, 2026. The Nicest Bug Every time the /dev/bigwave device is opened, the driver allocates a new kernel struct called inst which is stored in the private_data field of the fd . Within the inst is a sub-struct called job , which tracks the register values and status associated with an individual invocation of the BigWave hardware to perform a task. In order to submit some work to the bigo hardware, a process uses the ioctl BIGO_IOCX_PROCESS , which fetches Bigwave register values from the ioctl caller in AP userland, and places the job on a queue that gets picked up and used by a separate thread, the bigo worker thread. That means that an object whose lifetime is inherently bound to a file descriptor is transiently accessed on a separate kernel thread that isn’t explicitly synced to the existence of that file descriptor. During BIGO_IOCX_PROCESS ioctl handling, after submitting a job to get executed on bigo_worker_thread , the ioctl call enters wait_for_completion_timeout with a timeout of 16 seconds waiting for bigo_worker_thread to complete the job. After those 16 seconds, if bigo_worker_thread has not signaled job completion, the timeout period ends and the ioctl dequeues the job from the priority queue. However, if a sufficient number of previous jobs were stacked onto the bigo_worker_thread , it is possible that bigo_worker_

Over the past few years, several AI-powered features have been added to mobile phones that allow users to better search and understand their messages. One effect of this change is increased 0-click attack surface, as efficient analysis often requires message media to be decoded before the message is opened by the user. One such feature is audio transcription. Incoming SMS and RCS audio attachments received by Google Messages are now automatically decoded with no user interaction. As a result, audio decoders are now in the 0-click attack surface of most Android phones. I’ve spent a fair bit of time investigating these decoders, first reporting CVE-2025-49415 in the Monkey’s Audio codec on Samsung devices. Based on this research, the team reviewed the Dolby Unified Decoder, and Ivan Fratric and I reported CVE-2025-54957 . This vulnerability is likely in the 0-click attack surface of most Android devices in use today. In parallel, Seth Jenkins investigated a driver accessible from the sandbox the decoder runs in on a Pixel 9, and reported CVE-2025-36934. As I’ve shared this research, vendors as well as members of the security community have questioned whether such vulnerabilities are exploitable, as well as whether 0-click exploits are possible for all but the most well-resourced attackers in the modern Android Security environment. We were also asked whether code execution in the context of a media decoder is practically useful to an attacker and how platforms can reduce the risks such a capability presents to users. To answer these questions, Project Zero wrote a 0-click exploit chain targeting the Pixel 9. We hope this research will help defenders better understand how these attacks work in the wild, the strengths and weaknesses of Android’s security features with regards to preventing such attacks, and the importance of remediating media and driver vulnerabilities on mobile devices. The exploit will be detailed in three blog posts. Part 1 of this series will describe how we exploited CVE-2025-54957 to gain arbitrary code execution in the mediacodec context of a Google Pixel 9. Part 2 of this series will describe how we exploited CVE-2025-36934 to escalate privileges from mediacodec to kernel on this device. Part 3 will discuss lessons learned and recommendations for preventing similar exploits on mobile devices. The vulnerabilities discussed in these posts were fixed as of January 5, 2026. The Dolby Unified Decoder The Dolby Unified Decoder component (UDC) is a library that provides support for the Dolby Digital (DD) and Dolby Digital Plus (DD+) audio formats. These formats are also known as AC-3 and EAC-3 respectively. A public specification is available for these formats. The UDC is integrated into a variety of hardware and platforms, including Android, iOS, Windows and media streaming devices. It is shipped to most OEMs as a binary ‘blob’ with limited symbols, which is then statically linked into a shared library. On the Pixel 9, the UDC is i

On Thursday, a team of researchers led by Microsoft announced that they had discovered, and possibly patched, what they're terming a biological zero-day—an unrecognized security hole in a system that protects us from biological threats. The system at risk screens purchases of DNA sequences to determine when someone's ordering DNA that encodes a toxin or dangerous virus. But, the researchers argue, it has become increasingly vulnerable to missing a new threat: AI-designed toxins. How big of a threat is this? To understand, you have to know a bit more about both existing biosurveillance programs and the capabilities of AI-designed proteins. Catching the bad ones Biological threats come in a variety of forms. Some are pathogens, such as viruses and bacteria. Others are protein-based toxins, like the ricin that was sent to the White House in 2003. Still others are chemical toxins that are produced through enzymatic reactions, like the molecules associated with red tide . All of them get their start through the same fundamental biological process: DNA is transcribed into RNA, which is then used to make proteins. Read full article Comments

As we careen toward a future in which Google has final say over what apps you can run , the company has sought to assuage the community's fears with a blog post and a casual "backstage" video. Google has said again and again since announcing the change that sideloading isn't going anywhere, but it's definitely not going to be as easy. The new information confirms app installs will be more reliant on the cloud, and devs can expect new fees, but there will be an escape hatch for hobbyists. Confirming app verification status will be the job of a new system component called the Android Developer Verifier, which will be rolled out to devices in the next major release of Android 16. Google explains that phones must ensure each app has a package name and signing keys that have been registered with Google at the time of installation. This process may break the popular FOSS storefront F-Droid . It would be impossible for your phone to carry a database of all verified apps, so this process may require Internet access. Google plans to have a local cache of the most common sideloaded apps on devices, but for anything else, an Internet connection is required. Google suggests alternative app stores will be able to use a pre-auth token to bypass network calls, but it's still deciding how that will work. Read full article Comments

Over the past year, Meta has blanketed TV screens around the world with commercials touting the privacy of Whatsapp, its encrypted messenger with a monthly user base of 3 billion people. “It’s private,” one ad campaign featuring the former cast of the Modern Family TV show says. “On Whatsapp, no one can see or hear your personal messages … not even us,” a different series of ads declares. “Serious risks to user data” On Monday, the former head of security for the Meta-owed messaging app filed a federal whistleblower lawsuit that tells a far different narrative. The suit, filed in US District Court for the District of Northern California, recites a litany of purported security and privacy flaws that Meta not only didn’t fix after becoming aware of them, but also kept secret, allegedly in violation of a $5 billion settlement then-Whatsapp parent company Facebook reached with the Federal Trade Commission. The complaint was filed by Attaullah Baig, who became head of WhatsApp security in 2021. Read full article Comments

Extensions installed on almost 1 million devices have been overriding key security protections to turn browsers into engines that scrape websites on behalf of a paid service, a researcher said. The 245 extensions, available for Chrome, Firefox, and Edge, have racked up nearly 909,000 downloads, John Tuckner of SecurityAnnex reported . The extensions serve a wide range of purposes, including managing bookmarks and clipboards, boosting speaker volumes, and generating random numbers. The common thread among all of them: They incorporate MellowTel-js , an open source JavaScript library that allows developers to monetize their extensions. Intentional weakening of browsing protections Tuckner and critics say the monetization works by using the browser extensions to scrape websites on behalf of paying customers, which include AI startups, according to MellowTel founder Arsian Ali. Tuckner reached this conclusion after uncovering close ties between MellowTel and Olostep , a company that bills itself as "the world's most reliable and cost-effective Web scraping API." Olostep says its service “avoids all bot detection and can parallelize up to 100K requests in minutes.” Paying customers submit the locations of browsers they want to access specific webpages. Olostep then uses its installed base of extension users to fulfill the request. Read full article Comments