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Published: 7 September 2022

JOSE is "JSON Web Almost Everything" - JWA, JWS, JWE, JWT, JWK, JWKS with no dependencies using runtime's native crypto in Node.js, Browser, Cloudflare Workers, Electron, and Deno. The PBKDF2-based JWE key management algorithms expect a JOSE Header Parameter named `p2c` PBES2 Count, which determines how many PBKDF2 iterations must be executed in order to derive a CEK wrapping key. The purpose of this parameter is to intentionally slow down the key derivation function in order to make password brute-force and dictionary attacks more expensive. This makes the PBES2 algorithms unsuitable for situations where the JWE is coming from an untrusted source: an adversary can intentionally pick an extremely high PBES2 Count value, that will initiate a CPU-bound computation that may take an unreasonable amount of time to finish. Under certain conditions, it is possible to have the user's environment consume unreasonable amount of CPU time. 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. The `v1.28.2`, `v2.0.6`, `v3.20.4`, and `v4.9.2` releases limit the maximum PBKDF2 iteration count to `10000` by default. It is possible to adjust this limit with a newly introduced `maxPBES2Count` decryption option. If users are unable to upgrade their required library version, they 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).



Cvss 3 Severity Score


Score breakdown


Package Release Status
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(code not present)
focal Not vulnerable
(code not present)
jammy Not vulnerable
(code not present)
kinetic Ignored
(end of life, was needs-triage)
lunar Ignored
(end of life, was needs-triage)
mantic Needs triage

trusty Ignored
(end of standard support)
upstream Needs triage

xenial Ignored
(end of standard support)
Launchpad, Ubuntu, Debian
bionic Does not exist

focal Does not exist

jammy Needed

kinetic Not vulnerable
lunar Not vulnerable
mantic Not vulnerable
trusty Ignored
(end of standard support)
Released (4.9.2-1)
xenial Ignored
(end of standard support)

Severity score breakdown

Parameter Value
Base score 5.3
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Scope Unchanged
Confidentiality None
Integrity impact None
Availability impact Low
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L