A vulnerability in Playwright WebSocket allows users with valid access tokens to read files from the environment where the remote browser is running. CVE-2026-92811 affects versions that do not properly enforce the default restriction for the file://.
The vulnerability was reported on September 16, 2026, and according to the CVEFeed entry, affects browserless versions 1.44.0 through 2.56.7. The service is used to remotely execute Chromium, Chrome, or Firefox via Playwright and Puppeteer.
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How the Playwright WebSocket vulnerability works
Browserless exposes Playwright WebSocket so that an authorized client can connect to a headless browser located on a server or container. The ALLOW_FILE_PROTOCOL defaults to false, but affected versions do not consistently enforce this rule.
A remote user with a valid token can direct the browser to a file:// via Playwright WebSocket. This makes it possible to read files that are accessible to the container process, even if the administrator has not explicitly enabled access to the local file system.
CVE -2026-92811 is not an anonymous remote code execution. It requires a token to be in possession, so protecting tokens and limiting who can log in is critical. NVD rates it High with a score of 7.1because the primary impact is file confidentiality.
Who is at risk from the browserless vulnerability?
Browserless installations using versions 1.44.0 through 2.56.7 that allow third parties to acquire tokens are at risk. The exposure increases when tokens are stored in shared files, exposed in logs, or used by multiple groups without separation of rights.
The Playwright WebSocket route can operate on a private network, an internal automation system, or a public endpoint. In either case, a leaked token can translate into a vulnerability to access configuration files, temporary data, and other elements visible within the container.
The issue is particularly acute in environments where the remote browser connects to databases, storage services, or internal APIs. Even without access to the host operating system, container files can reveal keys, cookies, and parameters that enable further steps in an attack.
Organizations should examine connections to WebSocket endpoints, unusual file:// , and attempts to use old tokens. The search should cover both browserless logs and reverse proxies or gateways that mediate access.
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Immediate solution for browserless
The recommended action for CVE-2026-92811 is to upgrade browserless to version 2.57.0 or later. After updating, administrators should verify that ALLOW_FILE_PROTOCOL remains disabled and that the access policy on Playwright WebSocket endpoints is enforced as intended.
At the same time, it is necessary to immediately rotate all tokens that may have been exposed, restrict access to endpoints, and control the permissions of the process within the container. Isolating browserless from sensitive volumes reduces the extent of a possible file read.
Particular care is needed with automations that create a Playwright WebSocket connection for each task and then hold the same token for a long time. This practice makes operation easier, but increases the window of exploitation when a token is intercepted. Issuing new tokens per application and expiring them in a short period of time limits the potential damage.
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Remediation should not be limited to installing the new package. Security teams should examine whether files were read out of the expected flow, check environment variables, and confirm that configuration copies do not contain active credentials. In case of suspicious activity, container isolation and secret reissuance precede service restoration.
The SecNews technical team also recommends checking for Playwright WebSocket vulnerability fingerprints before and after the upgrade. Using the patched version, protecting tokens, and monitoring connections are the key three-pronged approach to mitigating the risk.
See also: Patch Tuesday September 2026: Microsoft fixes over 960 vulnerabilities
