China-Linked Espionage Groups Rapidly Share BlueMoon Exploit Kit Chaining Chrome and Windows Zero-Days
Proofpoint and Volexity report that at least four China-aligned espionage clusters, starting with APT31/TA412 on August 28, 2026, rapidly adopted the 'BlueMoon' kit chaining Chrome V8 zero-days CVE-2026-85046 and CVE-2026-87491 with Windows ALPC…
Proofpoint, with corroborating reporting from Volexity, identified a shared exploit kit dubbed BlueMoon that chains three zero-days: a Chromium V8 type-confusion RCE (CVE-2026-85046), a second V8 sandbox escape (CVE-2026-87491, which GBHackers characterizes as a WebAssembly sandbox escape; earlier reports described this flaw without a CVE), and a Windows kernel privilege-escalation flaw (CVE-2026-85880) abusing the Advanced Local Procedure Call mechanism. Proofpoint first observed the kit on August 28, 2026, in the hands of TA412 (APT31, also tracked as Violet Typhoon and JungleBamboo), which targeted US NGOs, mining, and commodity trading firms via spearphishing and deployed GemStone (also tracked as LONGTALE), a malicious Chrome extension masquerading as a Google Gemini AI companion that harvests keystrokes, cookies, screenshots, browsing history, and session tokens. Volexity documented campaigns detected September 1, 2026, in which UTA0560 and JungleBamboo ran byte-identical exploit shellcode delivered via links on legitimate US university websites vulnerable to reflected XSS; UTA0560 deployed the GRIMWEDGE JScript backdoor (C2: ocr.opusaccel[.]top) while JungleBamboo used the SUPERSTOMP loader to install LONGTALE. Volexity assessed a shared exploit developer sold the chain to separate Chinese operators, with medium confidence per GBHackers but low confidence per Security Affairs. Proofpoint's other clusters — UNK_LateNight (US aerospace/defense from September 2, ShadowPad via DLL sideloading), UNK_DoubleCheck (Vietnamese manufacturing), and UNK_QuietRacket (Indonesia and Singapore) — adopted the kit within days; fewer than 20 organizations were observed targeted. Both V8 bugs were patch-gap zero-days: the fix was committed to Chromium on August 7, 2026, but only reached stable Chrome on September 3, 2026, and maintainers weaponized public upstream commits. Artifacts including markdown handover documents, V8CTF references, diagnostic logging, and a curl-based default payload led researchers to suspect AI-assisted exploit development. Proofpoint suspects the ALPC exploit has existed since 2025 and expects BlueMoon to proliferate, possibly to criminal actors. Note: one merged report (Horizon3.ai) covered an unrelated story — the actively exploited N-able N-central pre-auth RCE CVE-2026-86218.
- BlueMoon chains three zero-days: Chromium V8 type-confusion RCE CVE-2026-85046, a second V8 sandbox escape CVE-2026-87491 (GBHackers describes it as a WebAssembly sandbox escape; Cyber Security News, The Register, and Security Affairs…
- Proofpoint first observed BlueMoon on August 28, 2026, used by TA412 (APT31, also tracked as Violet Typhoon and JungleBamboo) against US NGOs, mining, and commodity trading firms; Security Affairs framed adoption by four nation-state…
- Volexity detected campaigns on September 1, 2026, in which UTA0560 and JungleBamboo (APT31) ran byte-identical exploit shellcode but different payloads; Volexity assessed a shared exploit developer sold or shared the chain, with medium…
- UNK_LateNight used BlueMoon from September 2, 2026, against US aerospace/defense companies with RFQ phishing lures, deploying ShadowPad via DLL sideloading; UNK_DoubleCheck targeted Vietnamese manufacturers and UNK_QuietRacket targeted…
- Activity peaked September 2-3, 2026, before stable Chrome patching (CyberScoop).
- Patch-gap window: the V8 fix was committed to Chromium on August 7, 2026, but reached stable Chrome only on September 3, 2026; SecurityWeek reports all three flaws were patched between September 3 and September 2026 Patch Tuesday.
- CVE-2026-85880 reportedly works only on Windows 10 and Server 2019/2022 (Cyber Security News); Security Affairs says it uses ALPC and the Windows Notification Facility, while GBHackers locates the flaw in RtlpCreateServerAcl; Proofpoint…
- The GemStone (also tracked as LONGTALE) browser extension masquerades as an AI-powered Google Gemini companion, harvesting keystrokes, cookies, screenshots, browsing history, and session tokens, and bypasses Chrome profile integrity checks…
Coverage timelineoldest first · each row is one article
- · 7d agoHackers Chain Chrome and Windows Zero-Days in New BlueMoon Exploit Kit Attacks
Cyber Security News· 86
Multiple espionage actors, mostly China-nexus, are chaining Chrome V8 and Windows kernel zero-days (CVE-2026-85046, CVE-2026-85880) via the BlueMoon exploit kit against government and defense targets.
Vulnerabilities in this storyAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2026-85046 | Actively Exploited V8 Type Confusion in Google Chrome (CVE-2026-85046) Google Chrome versions prior to 152.0.7977.82 contain a type confusion flaw (CWE-843) in the V8 JavaScript engine, which mishandles object types during engine operations (public proof-of-concept writeups indicate it is reachable through array sorting and WebAssembly-related code paths). A remote attacker triggers the flaw simply by getting a user to open a crafted HTML page, with no privileges or authentication required. Successful exploitation lets the attacker execute arbitrary code inside the browser's sandbox, and public reporting shows it being chained with Windows zero-days (the 'BlueMoon' exploit kit) by Chinese espionage groups for broader compromise. Any user of an unpatched Chrome or another build embedding the affected V8 engine is exposed. The vulnerability is a zero-day that was actively exploited in the wild before patching, was added to CISA's KEV on 2026-09-04, and has five public proof-of-concept references. Do: Update Google Chrome to 152.0.7977.82 or later immediately, and apply the corresponding V8 fix in any Chromium-based browser in use. Federal agencies must apply mitigations in line with CISA BOD 26-04 and its cloud-services requirements, evaluating each asset's internet exposure. Because public reporting shows this flaw chained with Windows zero-days in 'BlueMoon' attacks, patch the related Windows vulnerabilities as well and hunt for signs of exploit-chain activity on high-exposure endpoints. | 8.8 | 1% | KEV PoC ×5 |
| massmultiple billions of users/installs (Chrome is the dominant desktop browser at roughly 65% market share, with an estimated 3+ billion active users, plus… | |
| CVE-2026-85880 | Heap-Based Buffer Overflow in Windows ALPC Enables Local Privilege Escalation CVE-2026-85880 is a heap-based buffer overflow in Windows Advanced Local Procedure Call (ALPC), the Windows mechanism for local inter-process communication. An authorized local attacker can trigger the overflow by submitting crafted input over ALPC, corrupting heap memory in the component that handles the request. Successful exploitation allows the attacker to execute code with elevated privileges, typically gaining SYSTEM-level control of the local host, which is especially valuable as a post-exploitation or sandbox-escape step. Affected products include Windows 10 (1607, 1809, 21H2, 22H2) and Windows Server 2012, 2016, 2019, and 2022, meaning most on-premises Windows estates are in scope. The flaw was fixed in Microsoft's record 974-CVE September 2026 Patch Tuesday and was added to CISA's KEV on 2026-09-08, confirming exploitation in the wild; press reports describe Windows zero-days being chained with a Chrome zero-day in 'BlueMoon' kit attacks, though the data does not explicitly confirm this CVE is the Windows flaw in that chain. Do: Apply Microsoft's September 2026 security (cumulative) updates for each affected Windows 10 and Windows Server build, as no public PoC or workaround is documented; CISA's KEV listing (added 2026-09-08) triggers BOD 26-04 patching requirements for federal agencies, so prioritize accordingly. Give priority to hosts where unprivileged users can log in — RDS/VDI servers, jump boxes, shared workstations — and to internet-exposed Windows servers, since an ALPC local privilege escalation is a common component in exploit chains combining remote code execution or browser flaws with elevation to SYSTEM. Organizations unable to patch promptly should follow BOD 26-04 guidance for cloud services or restrict local access to affected hosts until updates are applied. | 7.8 | <1% | KEV |
| mass≈100M+ Windows installations (Windows 10 1607–22H2 on consumer/enterprise endpoints plus widely deployed Windows Server 2012–2022) | |
| CVE-2026-86218 | Pre-Auth Static Code Injection RCE in N-able N-central (Exploited in the Wild) CVE-2026-86218 is a static code injection flaw (CWE-96) in N-able's N-central on-premises remote monitoring and management (RMM) platform, carrying a maximum CVSS 4.0 score of 10.0. An unauthenticated, remote attacker triggers it by sending crafted network input to the N-central server that is improperly neutralized and persisted into application-managed code, which the server then executes — no privileges (PR:N) or user interaction (UI:N) are required. Successful exploitation yields full server compromise with high impact on confidentiality, integrity, and availability, and because N-central acts as the management hub for downstream customer endpoints, compromise can expose the entire managed estate. Any organization running an affected N-central release (before 2026.3.1.14) — primarily MSPs and corporate IT departments using N-able RMM — is affected. The flaw is confirmed exploited in the wild: N-able patched it as a zero-day, CISA added it to the KEV catalog on 2026-09-08, and it is the fourth N-central hotfix in five weeks, though no public PoC is known and ransomware use is unknown. Do: Upgrade N-central to 2026.3.1.14 or later (or apply N-able's hotfix) immediately, as the flaw is in CISA's KEV catalog and BOD 26-04 timelines apply to federal stakeholders. Until patched, remove direct internet exposure of the N-central server (restrict to VPN/management networks via firewall allowlists) since no authentication is needed for exploitation. Because in-the-wild exploitation is confirmed, review internet-facing N-central servers for indicators of compromise such as unexpected processes, unusual child processes of the web service, and new or suspicious accounts. | 10.0 | <1% | KEV PoC ×2 |
| large≈ tens of thousands of deployed/internet-exposed N-central servers (order of magnitude ~10k+), each managing many downstream customer endpoints | |
| CVE-2026-87491 | Actively Exploited Out-of-Bounds Write in Google Chrome V8 CVE-2026-87491 is an out-of-bounds write (CWE-787) in the V8 JavaScript engine in Google Chrome, fixed in Chrome 153.0.8010.36, which Google shipped alongside roughly 230 other security fixes. An attacker can trigger the flaw remotely by luring a user (user interaction required) into opening a crafted HTML page that corrupts memory in V8. Successful exploitation allows the attacker to execute arbitrary code inside the Chrome browser sandbox, which constrains but does not eliminate the impact. All Google Chrome users running versions prior to 153.0.8010.36 are affected; because the flaw resides in V8, CISA tracks it as 'Google Chromium V8', and other Chromium-based browsers may inherit the fix in their own updates. The flaw is being actively exploited in the wild — it is the seventh actively exploited Chrome zero-day of 2026 and was added to CISA's KEV catalog on 2026-09-09 — though no public proof-of-concept is known and ransomware use is unknown. Do: Update Google Chrome to 153.0.8010.36 or later immediately (open Help > About Google Chrome to force the update and relaunch), and verify the version on all endpoints. Also patch headless or automated Chrome deployments (CI runners, scrapers, kiosks, CDP-based tooling) that may lag auto-updates, and prioritize remediation per CISA KEV and BOD 26-04 requirements for federal systems. No public PoC is known and ransomware use is unknown, but confirmed in-the-wild exploitation warrants urgent patching. | 8.8 | <1% | KEV |
| massbillions of installations (Chrome's install base exceeds 3 billion users) |