Call of Duty: WWII, a World War II-themed first-person shooter released in 2017, enjoyed a renaissance in player numbers this July as it landed on PC Game Pass for the first time, drawing in a vast new wave of players lured by nostalgia and the allure of a “new” classic. But in what is now a cautionary tale for both publishers and players, the game was taken offline for PC users after a wave of serious hacking incidents that leveraged unpatched remote code execution (RCE) exploits, transforming what was initially a community celebration into a stark reminder of the risks lurking within older live-service games.
The Breach: RCE Exploits Run Amok
Within days of Call of Duty: WWII’s Game Pass debut, reports began to flood social media and gaming forums about malicious actors using RCE vulnerabilities to seize control of unsuspecting players’ computers. The range of disruptions, documented in video clips circulating online, ranged from relatively benign—trolling with endless Notepad pop-ups—to far more serious: forcibly shutting down PCs, altering desktop wallpapers mid-stream, and launching explicit or offensive content without user consent. One video that rapidly went viral captured a streamer’s experience as their PC wallpaper was changed in real-time to an image of an Activision lawyer, underscoring just how direct and invasive these attacks had become.Though there have been no confirmed reports of data theft or permanent hardware damage, the mere fact that hackers could take such complete control over player computers—live and on-air—has set off alarm bells well beyond the gaming community. The incident raises uncomfortable questions about the future of long-lived online games, especially as more legacy titles are revived or preserved through subscription services like Game Pass.
What Is an RCE, and Why Is It So Dangerous?
Remote code execution, or RCE, is a type of software vulnerability that potentially allows an attacker to run any code they wish on a victim’s machine without physical access. In the context of Call of Duty: WWII, this meant that malicious code could be injected and executed as soon as a player connected to a hacker-controlled game session. This category of exploit is particularly devastating because, unlike garden-variety cheats or “aimbots,” RCEs go beyond the boundaries of the game itself, compromising the security of the entire system.RCE exploits are frequently ranked among the most critical vulnerabilities by security professionals. The United States Cybersecurity & Infrastructure Security Agency (CISA) considers RCE flaws high risk and regularly issues advisories when new examples arise. For average gamers, however, the abstract threat became shockingly real over the July holiday weekend, as tens of thousands flocked to a now-vulnerable title.
Legacy Tech, Modern Problems: Why Was WWII at Risk?
The risk facing Call of Duty: WWII players in 2025 can be traced to a confluence of technical and business decisions, many rooted in the game’s original 2017 design:1. P2P Matchmaking
Unlike more recent online shooters, which rely on dedicated servers for hosting multiplayer games, WWII utilizes peer-to-peer (P2P) networking. This means players’ PCs connect directly with one another to facilitate gameplay, rather than routing all game traffic through a secure intermediary. While cost-effective at launch, P2P makes it much easier for attackers to probe and exploit client-side vulnerabilities. The PC’s greater execution freedom relative to consoles only amplifies this risk.2. Absence of Modern Anti-Cheat: “Ricochet”
In 2019, Activision began rolling out its sophisticated “Ricochet” anti-cheat technology, designed to harden the codebase and add kernel-level defenses across its Call of Duty flagship games. However, WWII predates “Ricochet” and has not received a backported version of these protections. As a result, attack surfaces left unprotected by modern countermeasures are now well-documented among security researchers and malicious actors alike.3. Lack of Ongoing Security Patches
While Activision, recently acquired by Microsoft, receives commendation for keeping legacy online games live for nostalgic and new audiences, this incident exposes a double-edged sword: sustaining old titles without dedicating equivalent resources for ongoing code maintenance can lead to catastrophic vulnerabilities. As new exploits are discovered and publicized—often thanks to the thriving cottage industry of cheat tools and exploit sellers—older Call of Duty titles have become hunting grounds for cyber criminals.According to several cybersecurity researchers and ethical hackers, including those cited by Tom’s Hardware, vulnerabilities in Call of Duty matchmaking have been well-known within the industry for years, but not always rapidly addressed.
Was This Preventable? The Broader Security Context
While remote code execution vulnerabilities are a persistent risk in multiplayer gaming, several measures could have mitigated this crisis:- Retiring P2P Networking: A shift to dedicated server architectures greatly reduces the potential exposure of end-users to malicious packets or intentionally malformed game data.
- Regular Vulnerability Assessments: Routine code reviews and penetration testing could have uncovered exploitable code paths before hackers did.
- Backporting Anti-Cheat Technology: Integrating parts of “Ricochet” or similar modern security frameworks—even as a legacy patch—would likely have dissuaded more casual exploiters and raised the bar for attackers.
- Community Transparency: Formal disclosure programs and bug bounties for mature titles are common in the broader software world, but comparatively rare in the games industry. A more proactive approach could have encouraged white-hat researchers to flag vulnerabilities before they were weaponized in the wild.
The Fallout: Activision’s Response and the Community Reaction
As reports snowballed and player outrage mounted, Activision swiftly responded by taking Call of Duty: WWII offline for PC users—starting with the Microsoft Store version and, at press time, the Game Pass release as well. This partial shutdown was accompanied by a terse social media announcement: “Call of Duty: WWII on PC Microsoft Store was brought offline while we investigate reports of an issue.” The publisher’s decision to initially leave the Steam version online (despite its affected status) raised eyebrows, though subsequent community reporting suggested all PC versions were equally vulnerable.Some community members praised the quick action but questioned why so little seemed to have been done in the intervening years—especially since similar RCE exploits have plagued previous entries in the series, including Call of Duty: Modern Warfare 2 and Black Ops II.
Worse, evidence from prominent cheat/exploit sellers suggests that off-the-shelf tools capable of performing these RCE attacks have been available for some time. One such utility, as revealed by X user @LasagneManne, displayed functions like “kick player,” “God mode,” and a one-click “RCE” execution—a stark illustration of how routine these invasions have become for bad actors.
Strengths Exposed by the Incident
Despite the troubling events, some strengths in the response and the underlying ecosystem were apparent:- Rapid Incident Response: Compared to historic delays in addressing game hacking incidents, Activision’s decision to take the title offline quickly helped to contain further harm.
- Heightened Public Awareness: The highly visible nature of the attack, including live-streamed hacks, has both educated and alarmed the broader player base about the unique risks of online PC multiplayer. This event may ultimately push for better security hygiene across the industry.
Severe Risks and Ongoing Vulnerabilities
Nonetheless, the overall risks exposed by this incident are severe and multi-faceted:1. Total System Compromise
An RCE provides hackers with the same permissions as the affected user, granting nearly unlimited control—from stealing files and planted malware to running ransomware or using the victim’s PC as part of a botnet. While the attacks against WWII players so far have been more about trolling than outright financial harm, the ease with which full system access could be obtained is deeply concerning.2. Wider Ecosystem Exposure
Given the similarities in client code among Call of Duty’s annual entries, it is plausible that other legacy titles using the same networking architecture remain at risk, unless they have been thoroughly audited and re-patched in recent years. This raises important questions about liability and due diligence for titles that are actively marketed to new players—even years after launch.3. Impact on Game Preservation and Live-Service Longevity
The gaming industry is grappling with how best to keep classic titles alive in a world where always-online experiences require continued investment and vigilance. Without clear commitments to patch and secure legacy games, the reputation of subscription services like Game Pass may be indirectly impacted; the dream of “play anything, anytime” must be balanced against the security realities of aging software.4. Potential for Real-World Harm
As the attack unfolded, some players expressed concern that bad actors might escalate from pranks to more malicious outcomes—such as credential theft or direct monetization. It is sobering to realize that, but for dumb luck or shifting attacker priorities, this incident could have led to severe losses for individual users.Next Steps: Best Practices for Players and Publishers
With the Call of Duty: WWII PC servers offline until a full fix is rolled out, what can other players and studios learn from this episode?For Players:
- Avoid launching unpatched, older online games following public reports of active exploits.
- Keep operating systems and antivirus signatures up to date.
- Monitor official channels and trusted news sources for security advisories and rapidly developing events.
- Prioritize regular penetration testing and vulnerability assessments, even (or especially) for legacy titles enjoying a second life on modern services.
- Invest in secure matchmaking architectures that remove unnecessary avenues for attackers.
- Consider formal bug bounty programs to harness the expertise of ethical hackers.
- Communicate transparently and proactively with player communities during and after breaches, sharing clear patch timelines, risk analyses, and lessons learned.
Looking Ahead: Will This Change Anything?
The Call of Duty: WWII exploit saga is only the latest (and perhaps most visible) in a long line of security lapses impacting classic multiplayer games. As games-as-a-service becomes the norm and more titles are brought forward from the past for modern audiences, the need for continuous, dedicated security practices has never been clearer.For Microsoft, now the ultimate steward of the Call of Duty brand through its acquisition of Activision Blizzard, the task is nothing less than a reinvention of legacy game operations. Mere preservation—the act of keeping old servers live—is no longer enough if those servers harbor potential zero-days and serve as open doors to malicious actors.
Industry watchers, as well as everyday players, should expect a more robust approach to security “ownership” for back-catalog titles, lest this become the first of many such incidents in the new era of cross-platform, subscription-first gaming. Transparency, investment, and engagement—not just for today’s hot releases but for yesterday’s classics—will determine whether the future of digital game preservation is safe, sustainable, and truly playable for all.
Conclusion
The events that took Call of Duty: WWII offline this summer offer more than just a dramatic news headline—they illuminate the often-invisible infrastructure demands of live-service gaming in the modern era. While remote code execution vulnerabilities may rarely make front-page news outside of security circles, their power to disrupt, harm, and undermine trust is enormous. Publishers and players alike must now reckon with the real costs—and obligations—of keeping games big and small alive for a new generation. Only with ongoing vigilance, investment, and clear communication can the dream of accessible, secure gaming truly be realized.Source: Tom's Hardware Activision takes Call of Duty: WWII offline after hackers apparently disrupted the game with RCE exploits — malicious code wreaks havoc on PC gamers as bad actors take complete control of your computer
