Version Details and Security Vulnerabilities

flat helps flatten/unflatten nested Javascript objects. A vulnerability, which was classified as critical, was found in hughsk flat up to 5.0.0. This affects the function unflatten of the file index.js. The manipulation leads to improperly controlled modification of object prototype attributes ('prototype pollution'). It is possible to initiate the attack remotely. Upgrading to version 5.0.1 can address this issue. The name of the patch is 20ef0ef55dfa028caddaedbcb33efbdb04d18e13. It is recommended to upgrade the affected component. The identifier VDB-216777 was assigned to this vulnerability.

A Regular Expression Denial of Service (ReDoS) flaw was found in kangax html-minifier 4.0.0 because of the reCustomIgnore regular expression.

Versions of open before 6.0.0 are vulnerable to command injection when unsanitized user input is passed in.

The package does come with the following warning in the readme:

The same care should be taken when calling open as if you were calling child_process.exec directly. If it is an executable it will run in a new shell.

Recommendation

open is now the deprecated opn package. Upgrading to the latest version is likely have unwanted effects since it now has a very different API but will prevent this vulnerability.

Versions of the package cross-spawn before 7.0.5 are vulnerable to Regular Expression Denial of Service (ReDoS) due to improper input sanitization. An attacker can increase the CPU usage and crash the program by crafting a very large and well crafted string.

Versions of mem prior to 4.0.0 are vulnerable to Denial of Service (DoS). The package fails to remove old values from the cache even after a value passes its maxAge property. This may allow attackers to exhaust the system's memory if they are able to abuse the application logging.

Recommendation

Upgrade to version 4.0.0 or later.

Affected versions of yargs-parser are vulnerable to prototype pollution. Arguments are not properly sanitized, allowing an attacker to modify the prototype of Object, causing the addition or modification of an existing property that will exist on all objects.
Parsing the argument --foo.__proto__.bar baz' adds a bar property with value baz to all objects. This is only exploitable if attackers have control over the arguments being passed to yargs-parser.

Recommendation

Upgrade to versions 13.1.2, 15.0.1, 18.1.1 or later.

Impact

passing untrusted user input - even after sanitizing it - to SendStream.redirect() may execute untrusted code

Patches

this issue is patched in send 0.19.0

Workarounds

users are encouraged to upgrade to the patched version of express, but otherwise can workaround this issue by making sure any untrusted inputs are safe, ideally by validating them against an explicit allowlist

Details

successful exploitation of this vector requires the following:

1. The attacker MUST control the input to response.redirect()
2. express MUST NOT redirect before the template appears
3. the browser MUST NOT complete redirection before:
4. the user MUST click on the link in the template

Affected versions of mime are vulnerable to regular expression denial of service when a mime lookup is performed on untrusted user input.

Recommendation

Update to version 2.0.3 or later.

The package postcss versions before 7.0.36 or between 8.0.0 and 8.2.13 are vulnerable to Regular Expression Denial of Service (ReDoS) via getAnnotationURL() and loadAnnotation() in lib/previous-map.js. The vulnerable regexes are caused mainly by the sub-pattern

\/\*\s* sourceMappingURL=(.*)

PoC

var postcss = require("postcss")
function build_attack(n) {
    var ret = "a{}"
    for (var i = 0; i < n; i++) {
        ret += "/*# sourceMappingURL="
    }
    return ret + "!";
}

postcss.parse('a{}/*# sourceMappingURL=a.css.map */') for (var i = 1; i <= 500000; i++) {
    if (i % 1000 == 0) {
        var time = Date.now();
        var attack_str = build_attack(i) try {
            postcss.parse(attack_str) var time_cost = Date.now() - time;
            console.log("attack_str.length: " + attack_str.length + ": " + time_cost + " ms");
        } catch (e) {
            var time_cost = Date.now() - time;
            console.log("attack_str.length: " + attack_str.length + ": " + time_cost + " ms");
        }
    }
}

An issue was discovered in PostCSS before 8.4.31. It affects linters using PostCSS to parse external Cascading Style Sheets (CSS). There may be \r discrepancies, as demonstrated by @font-face{ font:(\r/*);} in a rule.

This vulnerability affects linters using PostCSS to parse external untrusted CSS. An attacker can prepare CSS in such a way that it will contains parts parsed by PostCSS as a CSS comment. After processing by PostCSS, it will be included in the PostCSS output in CSS nodes (rules, properties) despite being originally included in a comment.

Affected versions of static-eval pass untrusted user input directly to the global function constructor, resulting in an arbitrary code execution vulnerability when user input is parsed via the package.

Proof of concept

var evaluate = require('static-eval');
var parse = require('esprima').parse;
var src = '(function(){console.log(process.pid)})()';
var ast = parse(src).body[0].expression;
var res = evaluate(ast, {});
// Will print the process id

Recommendation

Update to version 2.0.0 or later.

Versions of static-evalprior to 2.0.2 pass untrusted user input directly to the global function constructor, resulting in an arbitrary code execution vulnerability when user input is parsed via the package.

Proof of concept

var evaluate = require('static-eval');
var parse = require('esprima').parse;

var src = process.argv[2];
var payload = '(function({x}){return x.constructor})({x:"".sub})("console.log(process.env)")()'
var ast = parse(payload).body[0].expression;
console.log(evaluate(ast, {x:1}));

Recommendation

Upgrade to version 2.0.2 or later.

Versions of extend prior to 3.0.2 (for 3.x) and 2.0.2 (for 2.x) are vulnerable to Prototype Pollution. The extend() function allows attackers to modify the prototype of Object causing the addition or modification of an existing property that will exist on all objects.

Recommendation

If you're using extend 3.x upgrade to 3.0.2 or later. If you're using extend 2.x upgrade to 2.0.2 or later.

The NPM package micromatch prior to version 4.0.8 is vulnerable to Regular Expression Denial of Service (ReDoS). The vulnerability occurs in micromatch.braces() in index.js because the pattern .* will greedily match anything. By passing a malicious payload, the pattern matching will keep backtracking to the input while it doesn't find the closing bracket. As the input size increases, the consumption time will also increase until it causes the application to hang or slow down. There was a merged fix but further testing shows the issue persisted prior to https://github.com/micromatch/micromatch/pull/266. This issue should be mitigated by using a safe pattern that won't start backtracking the regular expression due to greedy matching.

The NPM package braces fails to limit the number of characters it can handle, which could lead to Memory Exhaustion. In lib/parse.js, if a malicious user sends "imbalanced braces" as input, the parsing will enter a loop, which will cause the program to start allocating heap memory without freeing it at any moment of the loop. Eventually, the JavaScript heap limit is reached, and the program will crash.