Keep-alive HTTP and HTTPS connections can remain open and inactive for up to 2 minutes in Node.js 6.16.0 and earlier. Node.js 8.0.0 introduced a dedicated server.keepAliveTimeout which defaults to 5 seconds. The behavior in Node.js 6.16.0 and earlier is a potential Denial of Service (DoS) attack vector. Node.js 6.17.0 introduces server.keepAliveTimeout and the 5-second default.

Simultaneous Multi-threading (SMT) in processors can enable local users to exploit software vulnerable to timing attacks via a side-channel timing attack on 'port contention'.

In all versions of Node.js prior to 6.14.4, 8.11.4 and 10.9.0 when used with UCS-2 encoding (recognized by Node.js under the names `'ucs2'`, `'ucs-2'`, `'utf16le'` and `'utf-16le'`), `Buffer#write()` can be abused to write outside of the bounds of a single `Buffer`. Writes that start from the second-to-last position of a buffer cause a miscalculation of the maximum length of the input bytes to be written.

The HTTP parser in all current versions of Node.js ignores spaces in the `Content-Length` header, allowing input such as `Content-Length: 1 2` to be interpreted as having a value of `12`. The HTTP specification does not allow for spaces in the `Content-Length` value and the Node.js HTTP parser has been brought into line on this particular difference. The security risk of this flaw to Node.js users is considered to be VERY LOW as it is difficult, and may be impossible, to craft an attack that makes use of this flaw in a way that could not already be achieved by supplying an incorrect value for `Content-Length`. Vulnerabilities may exist in user-code that make incorrect assumptions about the potential accuracy of this value compared to the actual length of the data supplied. Node.js users crafting lower-level HTTP utilities are advised to re-check the length of any input supplied after parsing is complete.

The `'path'` module in the Node.js 4.x release line contains a potential regular expression denial of service (ReDoS) vector. The code in question was replaced in Node.js 6.x and later so this vulnerability only impacts all versions of Node.js 4.x. The regular expression, `splitPathRe`, used within the `'path'` module for the various path parsing functions, including `path.dirname()`, `path.extname()` and `path.parse()` was structured in such a way as to allow an attacker to craft a string, that when passed through one of these functions, could take a significant amount of time to evaluate, potentially leading to a full denial of service.

Node.js was affected by OpenSSL vulnerability CVE-2017-3737 in regards to the use of SSL_read() due to TLS handshake failure. The result was that an active network attacker could send application data to Node.js using the TLS or HTTP2 modules in a way that bypassed TLS authentication and encryption.

There is an overflow bug in the AVX2 Montgomery multiplication procedure used in exponentiation with 1024-bit moduli. No EC algorithms are affected. Analysis suggests that attacks against RSA and DSA as a result of this defect would be very difficult to perform and are not believed likely. Attacks against DH1024 are considered just feasible, because most of the work necessary to deduce information about a private key may be performed offline. The amount of resources required for such an attack would be significant. However, for an attack on TLS to be meaningful, the server would have to share the DH1024 private key among multiple clients, which is no longer an option since CVE-2016-0701. This only affects processors that support the AVX2 but not ADX extensions like Intel Haswell (4th generation). Note: The impact from this issue is similar to CVE-2017-3736, CVE-2017-3732 and CVE-2015-3193. OpenSSL version 1.0.2-1.0.2m and 1.1.0-1.1.0g are affected. Fixed in OpenSSL 1.0.2n. Due to the low severity of this issue we are not issuing a new release of OpenSSL 1.1.0 at this time. The fix will be included in OpenSSL 1.1.0h when it becomes available. The fix is also available in commit e502cc86d in the OpenSSL git repository.

Node.js v4.0 through v4.8.3, all versions of v5.x, v6.0 through v6.11.0, v7.0 through v7.10.0, and v8.0 through v8.1.3 was susceptible to hash flooding remote DoS attacks as the HashTable seed was constant across a given released version of Node.js. This was a result of building with V8 snapshots enabled by default which caused the initially randomized seed to be overwritten on startup.

The c-ares function `ares_parse_naptr_reply()`, which is used for parsing NAPTR responses, could be triggered to read memory outside of the given input buffer if the passed in DNS response packet was crafted in a particular way.

The crc32_big function in crc32.c in zlib 1.2.8 might allow context-dependent attackers to have unspecified impact via vectors involving big-endian CRC calculation.

The inflateMark function in inflate.c in zlib 1.2.8 might allow context-dependent attackers to have unspecified impact via vectors involving left shifts of negative integers.

inffast.c in zlib 1.2.8 might allow context-dependent attackers to have unspecified impact by leveraging improper pointer arithmetic.

inftrees.c in zlib 1.2.8 might allow context-dependent attackers to have unspecified impact by leveraging improper pointer arithmetic.

There is a carry propagating bug in the Broadwell-specific Montgomery multiplication procedure in OpenSSL 1.0.2 and 1.1.0 before 1.1.0c that handles input lengths divisible by, but longer than 256 bits. Analysis suggests that attacks against RSA, DSA and DH private keys are impossible. This is because the subroutine in question is not used in operations with the private key itself and an input of the attacker's direct choice. Otherwise the bug can manifest itself as transient authentication and key negotiation failures or reproducible erroneous outcome of public-key operations with specially crafted input. Among EC algorithms only Brainpool P-512 curves are affected and one presumably can attack ECDH key negotiation. Impact was not analyzed in detail, because pre-requisites for attack are considered unlikely. Namely multiple clients have to choose the curve in question and the server has to share the private key among them, neither of which is default behaviour. Even then only clients that chose the curve will be affected.

There is a carry propagating bug in the x86_64 Montgomery squaring procedure in OpenSSL 1.0.2 before 1.0.2k and 1.1.0 before 1.1.0d. No EC algorithms are affected. Analysis suggests that attacks against RSA and DSA as a result of this defect would be very difficult to perform and are not believed likely. Attacks against DH are considered just feasible (although very difficult) because most of the work necessary to deduce information about a private key may be performed offline. The amount of resources required for such an attack would be very significant and likely only accessible to a limited number of attackers. An attacker would additionally need online access to an unpatched system using the target private key in a scenario with persistent DH parameters and a private key that is shared between multiple clients. For example this can occur by default in OpenSSL DHE based SSL/TLS ciphersuites. Note: This issue is very similar to CVE-2015-3193 but must be treated as a separate problem.

If an SSL/TLS server or client is running on a 32-bit host, and a specific cipher is being used, then a truncated packet can cause that server or client to perform an out-of-bounds read, usually resulting in a crash. For OpenSSL 1.1.0, the crash can be triggered when using CHACHA20/POLY1305; users should upgrade to 1.1.0d. For Openssl 1.0.2, the crash can be triggered when using RC4-MD5; users who have not disabled that algorithm should update to 1.0.2k.

The tls.checkServerIdentity function in Node.js 0.10.x before 0.10.47, 0.12.x before 0.12.16, 4.x before 4.6.0, and 6.x before 6.7.0 does not properly handle wildcards in name fields of X.509 certificates, which allows man-in-the-middle attackers to spoof servers via a crafted certificate.

CRLF injection vulnerability in the ServerResponse#writeHead function in Node.js 0.10.x before 0.10.47, 0.12.x before 0.12.16, 4.x before 4.6.0, and 6.x before 6.7.0 allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via the reason argument.

Heap-based buffer overflow in the ares_create_query function in c-ares 1.x before 1.12.0 allows remote attackers to cause a denial of service (out-of-bounds write) or possibly execute arbitrary code via a hostname with an escaped trailing dot.

crypto/x509/x509_vfy.c in OpenSSL 1.0.2i allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) by triggering a CRL operation.