Node.js Vulnerabilities

A certificate validation bypass in Node.js https.Agent lets a cached TLS session authenticated under one CA policy be reused by a later request with a stricter policy. https.Agent.prototype.getName() assigns the same Agent and session-cache key to a request that omits ca and one that explicitly supplies ca: [], because an omitted value appends nothing to the key while an empty array stringifies to an empty string. The two policies differ: omitting ca uses the default trust store, while supplying ca replaces it. Since they share a key, a TLS session authenticated under the broader default policy is handed to a new connection made under the later ca: [] policy, and TLS 1.3 session resumption carries the earlier authentication forward, so the second request reports authorized === true and transmits confidential data to a server its own CA policy would reject on a fresh connection. This vulnerability affects Node.js 26.x, 24.x, and 22.x.

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Node.js discloses proxy credentials in ERR_PROXY_INVALID_CONFIG error messages. CVE-2026-48615 established that a proxy credential must not appear in a Node.js error message and redacted the username and password from ProxyConfig.href, but that fix missed four error paths in the same subsystem, one of them inside the same constructor, which interpolate the raw proxy URL, credentials included, into an ERR_PROXY_INVALID_CONFIG message. The proxy URL comes from the environment, but the defect is the sink: a secret that Node.js redacts everywhere else is emitted verbatim into a much wider audience than the process environment, such as stderr, container logs, log aggregation, and crash reporting services. This vulnerability affects Node.js 26.x, 24.x, and 22.x.

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A one-byte heap buffer overflow in Node.js HTTP/2 Alt-Svc handling lets a remote, unauthenticated attacker corrupt process memory. When an application passes an attacker-controlled value such as a request's :authority header to Http2Session.altsvc(), the AltSvc implementation in src/node_http2.cc allocates a buffer sized to the origin length and then writes it with a null terminator, placing one byte past the end of the allocation. A single request carrying a long but syntactically valid :authority triggers the out-of-bounds write, which aborts the process and serves as a remote heap-corruption primitive. This vulnerability affects Node.js 26.x and 24.x.

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An unauthenticated HTTP/2 client can exhaust Node.js server memory because inbound DATA queued on an undrained stream is charged to no session budget. Each inbound DATA frame creates one JavaScript Buffer view in the receiving stream's readable queue, but nothing charges that queue to current_session_memory_: the socket read buffer is accounted only during parsing and released immediately, so whatever stays queued is accounted to nothing. A peer that fills a stream's receive window with one-byte DATA frames pays about 10 wire bytes per frame while the server retains about 114 bytes per frame, so a single stream on one connection can retain hundreds of megabytes from tens of megabytes sent. maxSessionMemory neither bounds the growth nor refuses new streams, because Http2Session::CanAddStream gates admission on the same counter that never sees the queue. This vulnerability affects Node.js 26.x and 24.x.

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A NULL pointer dereference in Node.js HTTP/2 lets an unauthenticated client crash the server, over both TLS and cleartext, by cancelling file downloads. When the server serves a file with stream.respondWithFile() or stream.respondWithFD() and the client cancels the request, a StreamPipe used for the transfer is torn down in an order that leaves a NULL pointer which is then dereferenced, aborting the process. No crafted frames are needed, and a handful of cancelled requests against a default file-serving handler is enough. This vulnerability affects Node.js 26.x, 24.x, and 22.x.

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A per-host mutual-TLS authorization bypass in Node.js lets a client authorized for the default hostname reach a protected hostname it is not authorized for. When a TLS server assigns a hostname a different client-certificate CA with server.addContext(host, { ca: protectedCA }) but no server certificate in that SNI context, the per-host client CA is never installed and the handshake falls back to the default client CA. In src/crypto/crypto_tls.cc, CertCbDone installs the SNI context's CA only when setSniContext succeeds, but setSniContext returns false for a context with no server certificate, so a CA-only SNI context silently keeps the default CA. A client holding a certificate trusted by the default CA, but not the protected CA, can therefore complete mTLS to the protected hostname and read its response even with requestCert and rejectUnauthorized enabled, while a client certified by the protected CA is rejected. This vulnerability affects Node.js 26.x, 24.x, and 22.x.

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An uncatchable exception in the Node.js zlib streaming API lets a peer crash a process by disconnecting while data is being compressed. zlib.params() queues a flush and completes its work in that write's callback; if the stream is destroyed first, as pipeline() does when the peer goes away, Writable still invokes the callback with an error, but the callback ignores its arguments and asserts that the native handle still exists. The handle is gone, so an ERR_INTERNAL_ASSERTION is thrown from inside stream internals and bypasses the stream's error event, the params() callback, and the pipeline() callback, terminating the process. An application is affected only if it calls deflate.params() while streaming to a peer, which is uncommon. This vulnerability affects Node.js 26.x, 24.x, and 22.x.

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A Permission Model bypass in Node.js recursive file watching discloses the names of files and directories the process is not permitted to read. On macOS and Windows, fs.watch() and fs.promises.watch() in recursive mode are backed by the native libuv watcher: FSEventWrap::Start checks kFileSystemRead only once, on the watched root, and FSEventWrap::OnEvent then forwards every filename libuv reports (relative paths at any depth) to the JavaScript callback without checking that each path is covered by the read grant. Code running under --permission with an exact read grant on a directory can therefore learn names such as sub/secret.txt even though readdir on that subdirectory is denied. The flaw exposes names and timing metadata, not file contents, and requires macOS or Windows plus files created under the watched directory by another actor. This vulnerability affects Node.js 26.x, 24.x, and 22.x.

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The Node.js web service on VOS (previously Versa FlexVNF) is used for URL-based Zero Touch Provisioning (ZTP) of the VOS appliance and is not required after provisioning is complete. This service generates session identifiers using UUID version 1 (UUIDv1), which is derived from the system’s date and time and its MAC address. As a result, successive identifiers differ only slightly and can be predicted. An attacker who can predict a user’s session ID could hijack that user’s session. Versa’s security hardening guide for Hubs, Branches, and Controllers recommends disabling the Node.js web service after the initial provisioning of the VOS device. This vulnerability is not exploitable on VOS devices where the Node.js web service has been disabled.

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A flaw in Node.js TLS hostname verification allows a certificate with only a DNS SAN to authenticate an IP endpoint when the client connects using a non-canonical IPv4 spelling, such as `0177.0.0.1`, `0x7f.0.0.1`, `2130706433` or `127.1`. `tls.checkServerIdentity()` did not classify these hosts as IP addresses, but normalized them to their canonical form and matched the result against the certificate DNS names. A certificate containing `DNS:127.0.0.1` and no `IP Address:127.0.0.1` SAN was therefore accepted, while the same certificate is correctly rejected for `127.0.0.1`. Exploitation requires a certificate with a numeric DNS SAN issued by a CA trusted by the client, and a platform resolver that accepts these spellings, such as glibc. This vulnerability affects Node.js **26.x**, **24.x**, and **22.x**.

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A flaw in Node.js HTTP Agent connection reuse can cause a client to accept as valid a response that was sent before the client has sent the request. This is an incomplete fix of CVE-2026-48931. The guard that destroys idle keep-alive sockets when unexpected data arrives only runs when the event loop polls for I/O. If an unsolicited response has already reached the socket but has not been read yet when the socket is handed to a new request, for example because the event loop was busy with synchronous work, the guard is removed without seeing it and the data is parsed as the response to the new request. This vulnerability affects Node.js **26.x**, **24.x**, and **22.x**.

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A flaw in Node.js `crypto` causes the internal entropy caches used by `crypto.randomUUID()`, `crypto.randomUUIDv7()`, and `crypto.randomInt()` to be saved into user-land startup snapshots (`--build-snapshot`) and single executable applications built with `useSnapshot`. If any of these functions, or an API that relies on them such as `URL.createObjectURL()`, is called while the snapshot is built, every process started from that snapshot returns the same values until the cache is refilled: up to 127 UUIDs and about 1,000 `randomInt()` values. Identifiers expected to be unique can collide across processes, and values issued by one process can be predicted by observing another. This vulnerability affects Node.js **26.x**, **24.x**, and **22.x**.

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A flaw in the Node.js `zlib.ZipFile` API can cause it to return bytes that do not belong to the requested entry after the local and central header validation fails. When `zipEntry.modified` is read on an archive whose local header does not match its central directory, either directly or while compacting the archive, the validation error is caught but the parsed local header is left cached without a content offset. A later content read then returns attacker-controlled bytes from the start of the file instead of rejecting the archive, and CRC-32 verification still passes because the attacker controls the central directory CRC. A Node.js-based scanner can therefore approve different content from what another ZIP implementation extracts from the same archive. This vulnerability affects Node.js **26.x**.

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A flaw in Node.js Permission Model filesystem enforcement can grant access to paths that do not match a wildcard `--allow-fs-read` or `--allow-fs-write` rule. When the requested path is shorter than the prefix of a wildcard grant, the radix tree lookup stops comparing early and treats the path as a match. For example, `--allow-fs-read=/etc/passwd.*` also allows reading `/etc/passwd`. This requires the wildcard grant to sit directly under the root of the permission tree, for example when it is the only grant for that scope. This is a different root cause from CVE-2026-58043. This vulnerability affects Node.js **26.x**.

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A flaw in Node.js Permission Model filesystem enforcement leaves `fs.realpathSync()` without the required read permission checks. This is an incomplete fix of CVE-2026-21715, which only covered `fs.realpathSync.native()`. As a result, code running under `--permission` with restricted `--allow-fs-read` can still use `fs.realpathSync()` to check file existence, resolve symlink targets, and enumerate filesystem paths outside of permitted directories. This vulnerability affects Node.js **26.x**, **24.x**, and **22.x**.

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