There are 14 open security issues in bookworm.
12 important issues:
- CVE-2025-55130:
A flaw in Node.js’s Permissions model allows attackers to bypass `--allow-fs-read` and `--allow-fs-write` restrictions using crafted relative symlink paths. By chaining directories and symlinks, a script granted access only to the current directory can escape the allowed path and read sensitive files. This breaks the expected isolation guarantees and enables arbitrary file read/write, leading to potential system compromise. This vulnerability affects users of the permission model on Node.js v20, v22, v24, and v25.
- CVE-2025-55131:
A flaw in Node.js's buffer allocation logic can expose uninitialized memory when allocations are interrupted, when using the `vm` module with the timeout option. Under specific timing conditions, buffers allocated with `Buffer.alloc` and other `TypedArray` instances like `Uint8Array` may contain leftover data from previous operations, allowing in-process secrets like tokens or passwords to leak or causing data corruption. While exploitation typically requires precise timing or in-process code execution, it can become remotely exploitable when untrusted input influences workload and timeouts, leading to potential confidentiality and integrity impact.
- CVE-2025-55132:
A flaw in Node.js's permission model allows a file's access and modification timestamps to be changed via `futimes()` even when the process has only read permissions. Unlike `utimes()`, `futimes()` does not apply the expected write-permission checks, which means file metadata can be modified in read-only directories. This behavior could be used to alter timestamps in ways that obscure activity, reducing the reliability of logs. This vulnerability affects users of the permission model on Node.js v20, v22, v24, and v25.
- CVE-2025-59465:
A malformed `HTTP/2 HEADERS` frame with oversized, invalid `HPACK` data can cause Node.js to crash by triggering an unhandled `TLSSocket` error `ECONNRESET`. Instead of safely closing the connection, the process crashes, enabling a remote denial of service. This primarily affects applications that do not attach explicit error handlers to secure sockets, for example: ``` server.on('secureConnection', socket => { socket.on('error', err => { console.log(err) }) }) ```
- CVE-2025-59466:
We have identified a bug in Node.js error handling where "Maximum call stack size exceeded" errors become uncatchable when `async_hooks.createHook()` is enabled. Instead of reaching `process.on('uncaughtException')`, the process terminates, making the crash unrecoverable. Applications that rely on `AsyncLocalStorage` (v22, v20) or `async_hooks.createHook()` (v24, v22, v20) become vulnerable to denial-of-service crashes triggered by deep recursion under specific conditions.
- CVE-2026-21637:
A flaw in Node.js TLS error handling allows remote attackers to crash or exhaust resources of a TLS server when `pskCallback` or `ALPNCallback` are in use. Synchronous exceptions thrown during these callbacks bypass standard TLS error handling paths (tlsClientError and error), causing either immediate process termination or silent file descriptor leaks that eventually lead to denial of service. Because these callbacks process attacker-controlled input during the TLS handshake, a remote client can repeatedly trigger the issue. This vulnerability affects TLS servers using PSK or ALPN callbacks across Node.js versions where these callbacks throw without being safely wrapped.
- CVE-2026-21710:
A flaw in Node.js HTTP request handling causes an uncaught `TypeError` when a request is received with a header named `__proto__` and the application accesses `req.headersDistinct`.
When this occurs, `dest["__proto__"]` resolves to `Object.prototype` rather than `undefined`, causing `.push()` to be called on a non-array. This exception is thrown synchronously inside a property getter and cannot be intercepted by `error` event listeners, meaning it cannot be handled without wrapping every `req.headersDistinct` access in a `try/catch`.
* This vulnerability affects all Node.js HTTP servers on **20.x, 22.x, 24.x, and v25.x**
- CVE-2026-21713:
A flaw in Node.js HMAC verification uses a non-constant-time comparison when validating user-provided signatures, potentially leaking timing information proportional to the number of matching bytes. Under certain threat models where high-resolution timing measurements are possible, this behavior could be exploited as a timing oracle to infer HMAC values.
Node.js already provides timing-safe comparison primitives used elsewhere in the codebase, indicating this is an oversight rather than an intentional design decision.
This vulnerability affects **20.x, 22.x, 24.x, and 25.x**.
- CVE-2026-21714:
A memory leak occurs in Node.js HTTP/2 servers when a client sends WINDOW_UPDATE frames on stream 0 (connection-level) that cause the flow control window to exceed the maximum value of 2³¹-1. The server correctly sends a GOAWAY frame, but the Http2Session object is never cleaned up.
This vulnerability affects HTTP2 users on Node.js 20, 22, 24 and 25.
- CVE-2026-21715:
A flaw in Node.js Permission Model filesystem enforcement leaves `fs.realpathSync.native()` without the required read permission checks, while all comparable filesystem functions correctly enforce them.
As a result, code running under `--permission` with restricted `--allow-fs-read` can still use `fs.realpathSync.native()` to check file existence, resolve symlink targets, and enumerate filesystem paths outside of permitted directories.
This vulnerability affects **20.x, 22.x, 24.x, and 25.x** processes using the Permission Model where `--allow-fs-read` is intentionally restricted.
- CVE-2026-21716:
An incomplete fix for CVE-2024-36137 leaves `FileHandle.chmod()` and `FileHandle.chown()` in the promises API without the required permission checks, while their callback-based equivalents (`fs.fchmod()`, `fs.fchown()`) were correctly patched.
As a result, code running under `--permission` with restricted `--allow-fs-write` can still use promise-based `FileHandle` methods to modify file permissions and ownership on already-open file descriptors, bypassing the intended write restrictions.
This vulnerability affects **20.x, 22.x, 24.x, and 25.x** processes using the Permission Model where `--allow-fs-write` is intentionally restricted.
- CVE-2026-21717:
A flaw in V8's string hashing mechanism causes integer-like strings to be hashed to their numeric value, making hash collisions trivially predictable. By crafting a request that causes many such collisions in V8's internal string table, an attacker can significantly degrade performance of the Node.js process.
The most common trigger is any endpoint that calls `JSON.parse()` on attacker-controlled input, as JSON parsing automatically internalizes short strings into the affected hash table.
This vulnerability affects **20.x, 22.x, 24.x, and 25.x**.
2 issues left for the package maintainer to handle:
- CVE-2025-23085:
(postponed; to be fixed through a stable update)
A memory leak could occur when a remote peer abruptly closes the socket without sending a GOAWAY notification. Additionally, if an invalid header was detected by nghttp2, causing the connection to be terminated by the peer, the same leak was triggered. This flaw could lead to increased memory consumption and potential denial of service under certain conditions.
This vulnerability affects HTTP/2 Server users on Node.js v18.x, v20.x, v22.x and v23.x.
- CVE-2025-23166:
(postponed; to be fixed through a stable update)
The C++ method SignTraits::DeriveBits() may incorrectly call ThrowException() based on user-supplied inputs when executing in a background thread, crashing the Node.js process. Such cryptographic operations are commonly applied to untrusted inputs. Thus, this mechanism potentially allows an adversary to remotely crash a Node.js runtime.
You can find information about how to handle these issues in the security team's documentation.
![[bug history graph]](https://qa.debian.org/data/bts/graphs/n/nodejs.png){kind=link}