The request package through 2.88.2 for Node.js and the @cypress/request package prior to 3.0.0 allow a bypass of SSRF mitigations via an attacker-controller server that does a cross-protocol redirect (HTTP to HTTPS, or HTTPS to HTTP).

NOTE: The request package is no longer supported by the maintainer.

Summary

form-data uses Math.random() to select a boundary value for multipart form-encoded data. This can lead to a security issue if an attacker:

1. can observe other values produced by Math.random in the target application, and
2. can control one field of a request made using form-data

Because the values of Math.random() are pseudo-random and predictable (see: https://blog.securityevaluators.com/hacking-the-javascript-lottery-80cc437e3b7f), an attacker who can observe a few sequential values can determine the state of the PRNG and predict future values, includes those used to generate form-data's boundary value. The allows the attacker to craft a value that contains a boundary value, allowing them to inject additional parameters into the request.

This is largely the same vulnerability as was recently found in undici by parrot409 -- I'm not affiliated with that researcher but want to give credit where credit is due! My PoC is largely based on their work.

Details

The culprit is this line here: https://github.com/form-data/form-data/blob/426ba9ac440f95d1998dac9a5cd8d738043b048f/lib/form_data.js#L347

An attacker who is able to predict the output of Math.random() can predict this boundary value, and craft a payload that contains the boundary value, followed by another, fully attacker-controlled field. This is roughly equivalent to any sort of improper escaping vulnerability, with the caveat that the attacker must find a way to observe other Math.random() values generated by the application to solve for the state of the PRNG. However, Math.random() is used in all sorts of places that might be visible to an attacker (including by form-data itself, if the attacker can arrange for the vulnerable application to make a request to an attacker-controlled server using form-data, such as a user-controlled webhook -- the attacker could observe the boundary values from those requests to observe the Math.random() outputs). A common example would be a x-request-id header added by the server. These sorts of headers are often used for distributed tracing, to correlate errors across the frontend and backend. Math.random() is a fine place to get these sorts of IDs (in fact, opentelemetry uses Math.random for this purpose)

PoC

PoC here: https://github.com/benweissmann/CVE-2025-7783-poc

Instructions are in that repo. It's based on the PoC from https://hackerone.com/reports/2913312 but simplified somewhat; the vulnerable application has a more direct side-channel from which to observe Math.random() values (a separate endpoint that happens to include a randomly-generated request ID).

Impact

For an application to be vulnerable, it must:

• Use form-data to send data including user-controlled data to some other system. The attacker must be able to do something malicious by adding extra parameters (that were not intended to be user-controlled) to this request. Depending on the target system's handling of repeated parameters, the attacker might be able to overwrite values in addition to appending values (some multipart form handlers deal with repeats by overwriting values instead of representing them as an array)
• Reveal values of Math.random(). It's easiest if the attacker can observe multiple sequential values, but more complex math could recover the PRNG state to some degree of confidence with non-sequential values.

If an application is vulnerable, this allows an attacker to make arbitrary requests to internal systems.

Versions of the package tough-cookie before 4.1.3 are vulnerable to Prototype Pollution due to improper handling of Cookies when using CookieJar in rejectPublicSuffixes=false mode. This issue arises from the manner in which the objects are initialized.

Overview

Versions <=8.5.1 of jsonwebtoken library could be misconfigured so that legacy, insecure key types are used for signature verification. For example, DSA keys could be used with the RS256 algorithm.

Am I affected?

You are affected if you are using an algorithm and a key type other than the combinations mentioned below

| Key type | algorithm | |----------|------------------------------------------| | ec | ES256, ES384, ES512 | | rsa | RS256, RS384, RS512, PS256, PS384, PS512 | | rsa-pss | PS256, PS384, PS512 |

And for Elliptic Curve algorithms:

| alg | Curve | |-------|------------| | ES256 | prime256v1 | | ES384 | secp384r1 | | ES512 | secp521r1 |

How do I fix it?

Update to version 9.0.0. This version validates for asymmetric key type and algorithm combinations. Please refer to the above mentioned algorithm / key type combinations for the valid secure configuration. After updating to version 9.0.0, If you still intend to continue with signing or verifying tokens using invalid key type/algorithm value combinations, you’ll need to set the allowInvalidAsymmetricKeyTypes option to true in the sign() and/or verify() functions.

Will the fix impact my users?

There will be no impact, if you update to version 9.0.0 and you already use a valid secure combination of key type and algorithm. Otherwise, use the allowInvalidAsymmetricKeyTypes option to true in the sign() and verify() functions to continue usage of invalid key type/algorithm combination in 9.0.0 for legacy compatibility.

Overview

Versions <=8.5.1 of jsonwebtoken library can be misconfigured so that passing a poorly implemented key retrieval function (referring to the secretOrPublicKey argument from the readme link) will result in incorrect verification of tokens. There is a possibility of using a different algorithm and key combination in verification than the one that was used to sign the tokens. Specifically, tokens signed with an asymmetric public key could be verified with a symmetric HS256 algorithm. This can lead to successful validation of forged tokens.

Am I affected?

You will be affected if your application is supporting usage of both symmetric key and asymmetric key in jwt.verify() implementation with the same key retrieval function.

How do I fix it?

Update to version 9.0.0.

Will the fix impact my users?

There is no impact for end users

Overview

In versions <=8.5.1 of jsonwebtoken library, lack of algorithm definition and a falsy secret or key in the jwt.verify() function can lead to signature validation bypass due to defaulting to the none algorithm for signature verification.

Am I affected?

You will be affected if all the following are true in the jwt.verify() function:

• a token with no signature is received
• no algorithms are specified
• a falsy (e.g. null, false, undefined) secret or key is passed

How do I fix it?

Update to version 9.0.0 which removes the default support for the none algorithm in the jwt.verify() method.

Will the fix impact my users?

There will be no impact, if you update to version 9.0.0 and you don’t need to allow for the none algorithm. If you need 'none' algorithm, you have to explicitly specify that in jwt.verify() options.