How severe is CVE-2015-9235?

No CVSS score has been assigned to CVE-2015-9235 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2015-9235?

CVE-2015-9235 affects the following packages: jsonwebtoken (npm). Ecosystems affected: npm.

How do I fix CVE-2015-9235?

Update jsonwebtoken to 4.2.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2015-9235 is resolved across your whole dependency graph.

How do I detect CVE-2015-9235 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for jsonwebtoken, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2015-9235 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.

Is CVE-2015-9235 actively exploited in the wild?

Yes. There are 4 known exploit references for CVE-2015-9235, including 2 in-the-wild exploitations 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 CVE-2015-9235?

CVE-2015-9235 has an EPSS (Exploit Prediction Scoring System) score of 8.5%, placing it in the 95th 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 CVE-2015-9235?

CVE-2015-9235 is classified as Improper Input Validation (CWE-20), Broken Cryptographic Algorithm (CWE-327). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2015-9235 published, and has it been updated?

CVE-2015-9235 was published on October 9, 2018 and was last updated on September 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

CVE-2015-9235 — jsonwebtoken

Fix: auth0/node-jsonwebtoken@1bb584b

CVE-2015-9235 is a Improper Input Validation vulnerability in jsonwebtoken. 4 public exploit or proof-of-concept references are indexed, so weaponization risk is real. A fix is available for jsonwebtoken — see the affected versions and patch details below.

Verification Bypass in jsonwebtoken

Published

Oct 9, 2018

Updated

Sep 10, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

4 known

Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

8.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs95th percentile — riskier than 95% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

37Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream

jsonwebtokennpm

81.4Mdownloads / week

Description

Versions 4.2.1 and earlier of jsonwebtoken are affected by a verification bypass vulnerability. This is a result of weak validation of the JWT algorithm type, occuring when an attacker is allowed to arbitrarily specify the JWT algorithm.

Recommendation

Update to version 4.2.2 or later.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`jsonwebtoken`	all versions	4.2.2`npm install jsonwebtoken@4.2.2`

Affected Products

1 product · 1 configurations

Application

jsonwebtokenauth0

< 4.2.2

range

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.

In jsonwebtoken node module before 4.2.2 it is possible for an attacker …

timmclean.netNVDOct 2019

Report on github.com

github.comGithubSep 2023

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for jsonwebtoken, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update jsonwebtoken to 4.2.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2015-9235 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.

Frequently Asked Questions

Versions 4.2.1 and earlier of `jsonwebtoken` are affected by a verification bypass vulnerability. This is a result of weak validation of the JWT algorithm type, occuring when an attacker is allowed to arbitrarily specify the JWT algorithm. ## Recommendation Update to version 4.2.2 or later.