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Part of a story covered by 4 sources: “Mass-Scanning Campaign Exploits Vite CVE-2026-39364 to Steal AWS and Azure Cloud Credentials from Exposed Dev Servers” — merged summary and timeline →

Hackers Mass-Scan Exposed Vite Servers to Steal AWS and Azure Cloud Credentials

AI summary · glm-5.3

F5 honeypots record mass scanning of exposed Vite dev servers exploiting CVE-2026-39364 to harvest AWS and Azure cloud credentials.

F5 honeypots recorded 807 session-grouped attacks and roughly 32,000 raw events in August 2026 against internet-exposed Vite development servers, up from 1,732 events in the previous three months. Scanners abused CVE-2026-39364 (Vite 7.1.0-7.3.1, 8.0.0-8.0.4), bypassing server.fs.deny via @fs routes with ?raw/?import query parameters and double encoding to read .env files, AWS SSO caches, Azure tokens, and Terraform state. The same infrastructure also probed CVE-2025-29927 (Next.js), CVE-2025-30208, CVE-2025-31125 (KEV-listed January 2026), and CVE-2024-45811. Most traffic originated from Google Cloud IP ranges, with the US accounting for 17,297 events.

  • ~32,000 honeypot events in August 2026 versus 1,732 over prior three months
  • Query-string bypasses of server.fs.deny expose .env, AWS, Azure, and Terraform secrets
  • Scanners rotate forged User-Agents (Googlebot, GPTBot) and spoofed X-Forwarded-For headers
  • Upgrade to Vite 7.3.2/8.0.5+ and rotate all secrets on previously exposed servers

Vulnerabilities mentionedAll →

CVEVulnerabilityCVSSEPSSFlagsAffectedExposurePublished
CVE-2024-45811
Vite a frontend build tooling framework for javascript.

Vite a frontend build tooling framework for javascript. In affected versions the contents of arbitrary files can be returned to the browser. `@fs` denies access to files outside of Vite serving allow list. Adding `?import&raw` to the URL bypasses this limitation and returns the file content if it exists. This issue has been patched in versions 5.4.6, 5.3.6, 5.2.14, 4.5.5, and 3.2.11. Users are advised to upgrade. There are no known workarounds for this vulnerability.

NVD description · AI analysis pending
4.81%
CVE-2025-29927
Middleware Authorization Bypass in Vercel Next.js (CVE-2025-29927)

CVE-2025-29927 is a critical (CVSS 9.1) authorization bypass in Vercel's Next.js, a widely used React framework for full-stack web applications: when an application performs its authorization checks in middleware, a remote unauthenticated attacker can bypass those checks by sending a request containing the x-middleware-subrequest header, which causes the middleware to be skipped. Successful exploitation grants access to otherwise protected routes and resources without valid credentials, with high impact on confidentiality and integrity and no availability impact (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N). All Next.js releases starting in version 1.11.4 and prior to the branch-specific fixed versions 12.3.5, 13.5.9, 14.2.25, and 15.2.3 are affected, so any Next.js application that relies on middleware for authorization is exposed. Exploitation is not yet confirmed in the provided data: the flaw is not in CISA KEV and no public proof-of-concept is catalogued, but EPSS assigns a 99.2% (100th percentile) probability of exploitation within 30 days, and national authorities such as the UK NCSC are urging immediate patching.

Do: Upgrade Next.js to 12.3.5, 13.5.9, 14.2.25, or 15.2.3, matching your application's release branch. If patching is infeasible, block or strip the x-middleware-subrequest header from external requests at the reverse proxy, CDN, or WAF before they reach the Next.js application. Audit whether your applications perform authorization checks in middleware, and verify that protected routes cannot be reached without authentication after remediation.

9.199%
  • Vercel Next.js >= 1.11.4 and prior to 12.3.5 (fixed in 12.3.5)
  • Vercel Next.js 13.x line prior to 13.5.9 (fixed in 13.5.9)
  • Vercel Next.js 14.x line prior to 14.2.25 (fixed in 14.2.25)
  • +1 more
masspotentially millions of Next.js deployments worldwide, with plausibly hundreds of thousands of sites/apps actually exposed (only those using middleware for…
CVE-2025-30208
Unauthenticated Arbitrary File Read in Vite Dev Server via @fs Allow-List Bypass

Vite dev servers in versions prior to 6.2.3, 6.1.2, 6.0.12, 5.4.15, and 4.5.10 fail to enforce the `@fs` file-access allow list because trailing separators such as `?` are stripped in several places but are not accounted for in the query-string regexes. A remote, unauthenticated attacker triggers the flaw by appending `?raw??` or `?import&raw??` to a dev-server URL, bypassing the restriction and returning the contents of arbitrary files on the host if they exist. The impact is confidentiality only — arbitrary file read with no code execution or privilege escalation, consistent with the CVSS 3.1 score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N). Only projects that explicitly expose the Vite dev server to the network (via `--host` or the `server.host` config option) are affected; purely local development usage is not remotely exploitable. A public proof of concept is available in the GitHub advisory (GHSA-x574-m823-4x7w); the flaw is not yet in CISA KEV, but EPSS assigns a 75% probability of exploitation within 30 days (99th percentile), so opportunistic scanning is likely.

Do: Upgrade Vite to 6.2.3, 6.1.2, 6.0.12, 5.4.15, or 4.5.10 depending on your release branch. If you cannot upgrade immediately, stop exposing the dev server to untrusted networks (remove `--host` / set `server.host` to localhost) or firewall the dev-server port. Audit internet-facing hosts for running Vite dev servers and check access logs for requests containing `?raw??` or `?import&raw??`, which may indicate exploitation attempts.

7.575% PoC
  • vitejs vite All versions prior to the fixed releases 6.2.3, 6.1.2, 6.0.12, 5.4.15, and 4.5.10 (i.e., 6.2.x < 6.2.3, 6.1.x < 6.1.2, 6.0.x < 6.0.12, 5.4.x < 5.4.15, and 4.5.x
massmillions of installs run affected Vite versions (millions of weekly npm downloads); the remotely exploitable subset
CVE-2025-31125
Vite Dev Server Improper Access Control Exposes Protected Files (Actively Exploited)

CVE-2025-31125 is an improper access control flaw (CWE-284/CWE-200) in the Vite JavaScript frontend tooling's dev server, where HTTP requests using the '?inline&import' or '?raw?import' query parameters can read the contents of files the dev server should not serve, bypassing its file-access restrictions (server.fs.deny). An unauthenticated remote attacker (CVSS:3.1 AV:N/AC:L/PR:N/UI:N) triggers it by sending crafted requests with these query parameters to a running Vite dev server. The attacker gains read access to arbitrary files on the machine running the dev server, such as source code and .env files containing secrets, with high confidentiality impact and no integrity or availability impact. Only applications that explicitly expose the Vite dev server to the network via the --host flag or the server.host option are affected; production builds are not impacted. The flaw is being actively exploited: CISA added it to the Known Exploited Vulnerabilities catalog on 2026-01-22 (ransomware association unknown), and EPSS assigns a 58.5% probability of exploitation within 30 days (99th percentile).

Do: Upgrade Vite to 6.2.4, 6.1.3, 6.0.13, 5.4.16, or 4.5.11 depending on your release line. Until patched, do not expose the dev server to untrusted networks (remove --host/server.host or bind to localhost behind an access-controlled proxy), and review access logs for requests using ?inline&import or ?raw?import that retrieved sensitive files such as .env. As a KEV entry added 2026-01-22, U.S. federal agencies must apply vendor mitigations per BOD 22-01 or discontinue use if mitigations are unavailable.

7.558% KEV PoC
  • vitejs vite Releases before the fixed version in each line: 4.x < 4.5.11, 5.x < 5.4.16, 6.0.x < 6.0.13, 6.1.x < 6.1.3, 6.2.x < 6.2.4 (only when the dev server is exposed to
largeplausibly tens of thousands to ~100,000 network-exposed Vite dev servers, out of millions of total Vite users
CVE-2026-39364
Vite is a frontend tooling framework for JavaScript.

Vite is a frontend tooling framework for JavaScript. From 7.1.0 to before 7.3.2 and 8.0.5, on the Vite dev server, files that should be blocked by server.fs.deny (e.g., .env, *.crt) can be retrieved with HTTP 200 responses when query parameters such as ?raw, ?import&raw, or ?import&url&inline are appended. This vulnerability is fixed in 7.3.2 and 8.0.5.

NVD description · AI analysis pending
8.22% PoC
  • vitejs vite
  • vitejs vite\+

Indicators of compromiseAll →

TypeIndicatorContext
domainf5.comallowlists. Vulnerability scan distribution (Image Source: f5.com) Most activity originated from cloud-hosting infrastructure
domainserver.hostse it to LAN or public interfaces through the –host option, server.host configuration, container port mappings, Kubernetes ingress
Full article791 words · extracted from cybersecuritynews.com · click to collapse

Hackers are conducting a large-scale automated scanning campaign against internet-exposed Vite development servers, attempting to steal AWS credentials, Azure access tokens, environment variables, and Infrastructure-as-Code secrets.

F5 honeypot sensors recorded 807 session-grouped attacks and about 32,000 raw events in August 2026, a sharp increase from only 1,732 Vite-related file-read events observed over the previous three months.

The operation primarily exploited CVE-2026-39364, a high-severity Vite file-disclosure vulnerability published in April 2026. Attackers also tested older Vite access-control bypasses, suggesting the scanning infrastructure uses a broad exploit library rather than relying on a single vulnerability.

The rapid jump in activity demonstrates how quickly threat actors incorporate newly disclosed framework flaws into automated cloud credential-harvesting campaigns.

Vite Server Cloud Credentials

CVE-2026-39364 affects Vite 7.1.0 through 7.3.1 and Vite 8.0.0 through 8.0.4. The vulnerability lets unauthenticated attackers retrieve files that the server.fs.deny configuration should block, including .env files and certificates.

Vite provides an internal @fs route that serves files from the host filesystem during development. Although the deny-list mechanism is intended to prevent browsers from requesting sensitive content, specially constructed query parameters including ?raw, ?import&raw, and ?import&url&inline can bypass that protection and cause the server to return restricted files with an HTTP 200 response.

Attack activity trends
Attack activity trends (Image Source: F5)

Exploitation requires the Vite development server to be reachable over a network, the targeted file to reside within a directory permitted by server.fs.allow, and the file to match a server.fs.deny rule.

Vite binds to localhost by default, but developers can expose it to LAN or public interfaces through the –host option, server.host configuration, container port mappings, Kubernetes ingress rules, or cloud security-group mistakes.

F5 observed requests that combined the @fs endpoint with query-string bypasses, path traversal, and double-encoded separators. Examples included requests for .env, /root/.env, /proc/self/environ, and deeply encoded paths containing %252f.

Double encoding can help malicious requests pass through reverse proxies or web application firewalls that normalize paths differently from the backend server.

The scanners used a carefully assembled credential wordlist covering .env.local, .env.production, .env.staging, AWS credential files under common Linux user directories, AWS SSO caches, backup keys, rootkey.csv, aws-exports.js, and Amplify configuration files.

They also searched for Azure accessTokens.json and credential files, along with Terraform state, Terraform variables, Serverless Framework state, and other deployment artifacts.

Particularly notable was probing for /proc/self/cwd/.env, which can reveal the active application’s environment file without requiring an attacker to know its absolute installation path.

A successful response could expose API keys, database passwords, cloud access keys, session secrets, infrastructure addresses, and Terraform-managed resource data, potentially turning a development-server disclosure into broader cloud compromise.

The campaign sent HTTP/1.0 requests with Connection: close, a pattern consistent with lightweight automated scanners.

Requests rotated forged User-Agent strings impersonating Googlebot, ClaudeBot, GPTBot, PerplexityBot, OAI-SearchBot, and Amazonbot, while fabricated X-Forwarded-For and X-Real-IP headers attempted to confuse log analysis or evade poorly implemented IP allowlists.

Vulnerability scan distribution
Vulnerability scan distribution (Image Source: f5.com)

Most activity originated from cloud-hosting infrastructure, particularly addresses in Google Cloud Platform’s 34.x and 35.x ranges.

The United States accounted for 17,297 recorded events, followed by Belgium with 4,407, the Netherlands with 4,011, Singapore with 2,842, Taiwan with 1,994, and Japan with 1,353.

A subset of the same infrastructure also probed CVE-2025-29927, a Next.js middleware authorization bypass, suggesting the operators scan multiple web-development frameworks simultaneously.

The Vite traffic also triggered signatures for CVE-2025-30208, CVE-2025-31125, and CVE-2024-45811, all involving related file-access bypass techniques.

CISA added CVE-2025-31125 to its Known Exploited Vulnerabilities catalog in January 2026, reinforcing that exposed Vite development services are already being targeted in real-world activity.

Organizations should upgrade affected installations to Vite 7.3.2, 8.0.5, or newer supported releases and remove development servers from public-facing networks.

Security teams should audit Docker Compose files, Kubernetes services, ingress configurations, reverse proxies, firewall rules, and cloud security groups for exposed development ports, particularly Vite’s commonly used port 5173.

Defenders should also inspect HTTP logs for requests containing /@fs/, suspicious raw or import query parameters, encoded traversal sequences, and attempts to retrieve environment, AWS, Azure, Terraform, or /proc files.

Do not trust bot identities solely from User-Agent strings; validate crawler access with appropriate IP and reverse-DNS verification. Any organization that exposed an unpatched Vite server should assume attackers may have collected accessible secrets.

AWS keys, Azure tokens, database credentials, API secrets, signing keys, and Terraform-managed credentials should be revoked or rotated, followed by a review of cloud audit logs for unauthorized authentication, privilege escalation, persistence, and resource creation.

Learn 7 Metric-Gated AI SOC Deployment Phases – Download Free AI SOC Deployment Playbook 2026.

Guru Baranhttps://cybersecuritynews.com

Gurubaran KS is a cybersecurity analyst, and Journalist with a strong focus on emerging threats and digital defense strategies. He is the Co-Founder and Editor-in-Chief of Cyber Security News, where he leads editorial coverage on global cybersecurity developments.

Text extracted automatically; images, tables and formatting may be missing. Original: https://cybersecuritynews.com/vite-servers-under-attack/