Denial of Service (DoS) Affecting jose-browser-runtime package, versions <3.20.4 >=4.0.0 <4.9.2



    Attack Complexity High
    Availability High
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5.3 medium

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  • published 8 Sep 2022
  • disclosed 8 Sep 2022
  • credit Tom Tervoort, Filip Skokan

How to fix?

Upgrade jose-browser-runtime to version 3.20.4, 4.9.2 or higher.


jose-browser-runtime is a (Browser Runtime) 'JSON Web Almost Everything' - JWA, JWS, JWE, JWT, JWK with no dependencies Affected versions of this package are vulnerable to Denial of Service (DoS) by allowing an attacker to intentionally pick an extremely high PBES2 Count value which will initiate a CPU-bound computation that may take an unreasonable amount of time to finish.

Note: The impact is limited only to users utilizing the JWE decryption APIs with symmetric secrets to decrypt JWEs from untrusted parties who do not limit the accepted JWE Key Management Algorithms (alg Header Parameter) using the keyManagementAlgorithms (or algorithms in v1.x) decryption option or through other means.


Users who are unable to upgrade to the fixed version have two options depending on whether they expect to receive JWEs using any of the three PBKDF2-based JWE key management algorithms. They can use the keyManagementAlgorithms decryption option to disable accepting PBKDF2 altogether, or they can inspect the JOSE Header prior to using the decryption API and limit the PBKDF2 iteration count (p2c Header Parameter).


Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its intended and legitimate users.

Unlike other vulnerabilities, DoS attacks usually do not aim at breaching security. Rather, they are focused on making websites and services unavailable to genuine users resulting in downtime.

One popular Denial of Service vulnerability is DDoS (a Distributed Denial of Service), an attack that attempts to clog network pipes to the system by generating a large volume of traffic from many machines.

When it comes to open source libraries, DoS vulnerabilities allow attackers to trigger such a crash or crippling of the service by using a flaw either in the application code or from the use of open source libraries.

Two common types of DoS vulnerabilities:

  • High CPU/Memory Consumption- An attacker sending crafted requests that could cause the system to take a disproportionate amount of time to process. For example, commons-fileupload:commons-fileupload.

  • Crash - An attacker sending crafted requests that could cause the system to crash. For Example, npm ws package