CVE-2023-49290 Malicious parameters can cause a denial of service in lestrrat-go/jwx

Medium 5.3 Published 4 Dec 2023 Updated 29 May 2025

An attacker can cause a denial of service in the lestrrat-go/jwx library by setting an excessively high p2c parameter in JWE headers.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2023-49290?

CVE-2023-49290 is a medium-severity denial of service vulnerability in lestrrat-go jwx, published on 4 Dec 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

lestrrat-go/jwx is a Go module implementing various JWx (JWA/JWE/JWK/JWS/JWT, otherwise known as JOSE) technologies. A p2c parameter set too high in JWE's algorithm PBES2-* could lead to a denial of service. The JWE key management algorithms based on PBKDF2 require a JOSE Header Parameter called p2c (PBES2 Count). This parameter dictates the number of PBKDF2 iterations needed to derive a CEK wrapping key. Its primary purpose is to intentionally slow down the key derivation function, making password brute-force and dictionary attacks more resource- intensive. Therefore, if an attacker sets the p2c parameter in JWE to a very large number, it can cause a lot of computational consumption, resulting in a denial of service. This vulnerability has been addressed in commit `64f2a229b` which has been included in release version 1.2.27 and 2.0.18. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Weakness: CWE-400

Which versions are affected by CVE-2023-49290?

6 open source packages ship an affected version, including github.com/lestrrat-go/jwx and github.com/lestrrat-go/jwx/v2. It affects 1 product.

Package	Affected	Fixed in
`github.com/lestrrat-go/jwx` Go	All versions	`1.2.27`
`github.com/lestrrat-go/jwx` Go	All versions	`1.2.27`
`github.com/lestrrat-go/jwx` Go	All versions	`1.2.27`
`github.com/lestrrat-go/jwx/v2` Go	All versions	`2.0.18`
`github.com/lestrrat-go/jwx/v2` Go	All versions	`2.0.18`
`github.com/lestrrat-go/jwx/v2` Go	All versions	`2.0.18`

Products include Lestrrat-Go Jwx.

How do I fix CVE-2023-49290?

Upgrade github.com/lestrrat-go/jwx to 1.2.27 or later.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2023-49290 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-49290 exists.

Sources

Also known as GHSA-7f9x-gw85-8grf, GO-2023-2379, MINI-2v42-w5h3-9jwf, MINI-528m-5c78-877j, MINI-8xvj-jv4h-j35x, MINI-fxcj-487f-82g9 and 8 more.