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Denoland Deno vulnerabilities, page 2

39 vulnerabilities

Known vulnerabilities in Denoland Deno, newest first, with CVSS severity, EPSS, KEV listings, ransomware use and the affected versions.

CVE-2026-55517Crates.Iodeno+23mo ago23-06-2026 17:24

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.7.5, a Deno program that opens a client WebSocket connection could be crashed by the remote server. While handling the WebSocket handshake response, Deno parsed the Sec-WebSocket-Protocol and Sec-WebSocket-Extensions response headers in a way that assumed their bytes were always printable ASCII. A response header containing non-visible-ASCII bytes (0x80-0xFF) caused a panic that aborted the entire Deno process. This vulnerability is fixed in 2.7.5.CVE-2026-103473denolanddeno20d ago30-09-2026 17:22

Deno versions 2.7.0 through 2.9.7 on Windows contain a command injection vulnerability in node:child_process where shell arguments are escaped for the wrong shell type. Attackers can inject OS commands by passing untrusted arguments with the shell option, allowing arbitrary command execution with Deno process privileges.CVE-2026-27190Crates.Iodeno+28mo ago20-02-2026 20:52

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.6.8, a command injection vulnerability exists in Deno's node:child_process implementation. This vulnerability is fixed in 2.6.8.CVE-2026-22863Crates.Iodeno+29mo ago15-01-2026 22:53

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Before 2.6.0, node:crypto doesn't finalize cipher. The vulnerability allows an attacker to have infinite encryptions. This can lead to naive attempts at brute forcing, as well as more refined attacks with the goal to learn the server secrets. This vulnerability is fixed in 2.6.0.CVE-2026-22864Crates.Iodeno+29mo ago15-01-2026 22:58

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Before 2.5.6, a prior patch aimed to block spawning Windows batch/shell files by returning an error when a spawned path’s extension matched .bat or .cmd. That check performs a case-sensitive comparison against lowercase literals and therefore can be bypassed when the extension uses alternate casing (for example .BAT, .Bat, etc.). This vulnerability is fixed in 2.5.6.CVE-2026-44726Crates.Iodeno+23mo ago23-06-2026 17:24

Deno is a JavaScript, TypeScript, and WebAssembly runtime. From 2.0.0 until 2.7.8, a flaw in Deno's Node.js tls compatibility layer could cause a TLS client to transmit application data in plaintext after a connection retry. When `autoSelectFamily was enabled and the first address-family attempt failed, the socket reinitialization path reused a stale TLS upgrade hook that was bound to the original, failed handle. As a result, the replacement TCP connection was never upgraded to TLS, and any data the application wrote before the secureConnect event travelled over the network unencrypted. A network attacker positioned to cause the initial connection attempt to fail (for example, by dropping IPv6 traffic on a dual-stack host) could deterministically trigger the fallback path and observe or tamper with traffic that the application believed was TLS-protected. This vulnerability is fixed in 2.7.8.CVE-2026-49411Crates.Iodeno+23mo ago23-06-2026 17:18

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.8.0, the Node.js compatibility TCP path checked the permission against the original hostname string before resolution and then did not re-check after resolution. A caller could therefore pass a numeric alias of an IP address (for example the decimal integer 2130706433 or the hex form 0x7f000001, both of which resolve to 127.0.0.1) and reach the denied destination through node:net.connect or node:http.request's { host, port } options form. This vulnerability is fixed in 2.8.0.CVE-2026-49859Crates.Iodeno+23mo ago23-06-2026 17:14

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.8.1, when fetch() was called, Deno checked the destination hostname against --deny-net rules but did not re-check the IP addresses that hostname resolved to. An attacker-controlled script could use a specially crafted domain name that passes the hostname check yet resolves to a denied IP, bypassing the network restriction entirely. This vulnerability is fixed in 2.8.1.CVE-2026-49402Crates.Iodeno+23mo ago23-06-2026 17:20

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.7.10, Deno's node:child_process implementation provided an escapeShellArg() helper used when callers passed shell: true to spawn / spawnSync / exec and friends. On Windows, the helper failed to quote arguments that contained cmd.exe metacharacters and did not neutralize % (which cmd.exe expands even inside double-quoted strings). An attacker who controlled any portion of an argument passed to such a call could inject arbitrary additional commands into the spawned cmd.exe invocation. This vulnerability is fixed in 2.7.10.CVE-2026-49401Crates.Iodeno+23mo ago23-06-2026 17:22

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.7.14, Deno's permission system enforces filesystem and execution restrictions by comparing the requested path against the path supplied to --deny-read, --deny-write, --deny-run, or --deny-ffi. On macOS, that comparison was done at the raw-byte level while the APFS filesystem treats different Unicode spellings of the same name as the same file. That means a program could reach a denied path by spelling it differently than the deny rule. This vulnerability is fixed in 2.7.14.CVE-2026-49983Crates.Iodeno+23mo ago23-06-2026 17:16

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.8.1, environment access is gated by the env permission. You can deny it with --deny-env, or restrict it to a specific allowlist with --allow-env=FOO,BAR. The expectation is that a program running without env permission cannot change process.env. process.loadEnvFile() (the Node-compatible API for loading variables from a .env file) does not honor this. It only checks that the program has read permission for the dotenv file, then writes every key in that file into the process environment — even when env access is denied. In effect, --allow-read plus a writable or attacker-controlled .env file is enough to defeat --deny-env. This vulnerability is fixed in 2.8.1.CVE-2026-49406Crates.Iodeno+23mo ago23-06-2026 17:19

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.7.12, when Deno was run in BYONM mode (nodeModulesDir: "manual"), the module resolver did not validate that a package's resolved entrypoint stayed within its node_modules/<pkg>/ directory. A malicious package.json whose main field contained .. segments was able to resolve to an arbitrary path on disk, and the resolver then read that file without consulting the --allow-read allowlist. This let a require("evil-pkg") call return the contents of a file that a direct Deno.readTextFileSync(...) call would have been blocked from reading. This vulnerability is fixed in 2.7.12.CVE-2026-49860Crates.Iodeno+23mo ago23-06-2026 17:15

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.8.1, when a WebSocket connection was opened, Deno checked the destination hostname against --deny-net rules but did not re-check the IP addresses that hostname resolved to. An attacker-controlled script could use a specially crafted domain name that passes the hostname check yet resolves to a denied IP, bypassing the network restriction entirely. This vulnerability is fixed in 2.8.1.CVE-2026-49440Crates.Iodeno+23mo ago23-06-2026 17:13

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.8.1, node:crypto.checkPrime(candidate[, options][, callback]) and crypto.checkPrimeSync(candidate[, options]) ran no Miller-Rabin rounds at all when the caller left options.checks at its default of 0. In that mode, the only test applied to the candidate was trial division by the primes up to 17,863. Any composite whose smallest prime factor exceeds that bound — for example the product of two primes just above it, such as 17,881 × 17,891 — was reported as true ("probably prime"). The same divergence affected the lower-level op_node_check_prime / op_node_check_prime_bytes paths that the polyfill calls into. This vulnerability is fixed in 2.8.1.CVE-2026-32260Crates.Iodeno+27mo ago12-03-2026 19:41

Deno is a JavaScript, TypeScript, and WebAssembly runtime. From 2.7.0 to 2.7.1, A command injection vulnerability exists in Deno's node:child_process polyfill (shell: true mode) that bypasses the fix for CVE-2026-27190. The two-stage argument sanitization in transformDenoShellCommand (ext/node/polyfills/internal/child_process.ts) has a priority bug: when an argument contains a $VAR pattern, it is wrapped in double quotes (L1290) instead of single quotes. Double quotes in POSIX sh do not suppress backtick command substitution, allowing injected commands to execute. An attacker who controls arguments passed to spawnSync or spawn with shell: true can execute arbitrary OS commands, bypassing Deno's permission system. This vulnerability is fixed in 2.7.2.CVE-2023-22499chainguarddeno+43y ago17-01-2023 20:23

Deno is a runtime for JavaScript and TypeScript that uses V8 and is built in Rust. Multi-threaded programs were able to spoof interactive permission prompt by rewriting the prompt to suggest that program is waiting on user confirmation to unrelated action. A malicious program could clear the terminal screen after permission prompt was shown and write a generic message. This situation impacts users who use Web Worker API and relied on interactive permission prompt. The reproduction is very timing sensitive and can’t be reliably reproduced on every try. This problem can not be exploited on systems that do not attach an interactive prompt (for example headless servers). The problem has been fixed in Deno v1.29.3; it is recommended all users update to this version. Users are advised to upgrade. Users unable to upgrade may run with --no-prompt flag to disable interactive permission prompts.CVE-2023-28445Crates.Iodeno+63y ago23-03-2023 23:23

Deno is a runtime for JavaScript and TypeScript that uses V8 and is built in Rust. Resizable ArrayBuffers passed to asynchronous functions that are shrunk during the asynchronous operation could result in an out-of-bound read/write. It is unlikely that this has been exploited in the wild, as the only version affected is Deno 1.32.0. Deno Deploy users are not affected. The problem has been resolved by disabling resizable ArrayBuffers temporarily in Deno 1.32.1. Deno 1.32.2 will re-enable resizable ArrayBuffers with a proper fix. As a workaround, run with `--v8-flags=--no-harmony-rab-gsab` to disable resizable ArrayBuffers.CVE-2023-28446Crates.Iodeno+33y ago24-03-2023 19:46

Deno is a simple, modern and secure runtime for JavaScript and TypeScript that uses V8 and is built in Rust. Arbitrary program names without any ANSI filtering allows any malicious program to clear the first 2 lines of a `op_spawn_child` or `op_kill` prompt and replace it with any desired text. This works with any command on the respective platform, giving the program the full ability to choose what program they wanted to run. This problem can not be exploited on systems that do not attach an interactive prompt (for example headless servers). This issue has been patched in version 1.31.2.CVE-2023-33966Crates.Iodeno+43y ago31-05-2023 17:15

Deno is a runtime for JavaScript and TypeScript. In deno 1.34.0 and deno_runtime 0.114.0, outbound HTTP requests made using the built-in `node:http` or `node:https` modules are incorrectly not checked against the network permission allow list (`--allow-net`). Dependencies relying on these built-in modules are subject to the vulnerability too. Users of Deno versions prior to 1.34.0 are unaffected. Deno Deploy users are unaffected. This problem has been patched in Deno v1.34.1 and deno_runtime 0.114.1 and all users are recommended to update to this version. No workaround is available for this issue.