CVE-2016-10555

mediumpriority · track · 38EPSS 0.048 · 92 %ileexploit · PoCEUUS

grimoire priorityP1 · Urgent

Exploitable?

Public exploit

3 exploits · PoC

Likely / severe?

4.78% (92nd) EPSS

CVSS 4 · medium

Is it mine?

3 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · nvd · osv

EPSS · scored 2026-10-27

Since "algorithm" isn't enforced in jwt.decode()in jwt-simple 0.3.0 and earlier, a malicious user could choose what algorithm is sent sent to the server. If the server is expecting RSA but is sent HMAC-SHA with RSA's public key, the server will think the public key is actually an HMAC private key. This could be used to forge any data an attacker wants.

cvss

Technical severity, 0–10. One row per scoring source.

6.5

010

base score 0–10 · higher = more severe · hover a vector to decode

v2.04mediumAV:N/AC:L/Au:S/C:N/I:P/A:Nprimary · NVD / NIST USexploitability 8 · impact 2.9

v3.06.5mediumCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:Nprimary · NVD / NIST USexploitability 2.8 · impact 3.6

v3.06.2mediumCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N/E:Psecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-310USprimaryCWE-20USCWE-20US

exploits (3)

Public proof-of-concept and weaponised exploit code.

affected products (3)

Products and version ranges known to be affected.

HackerOne jwt-simple node module≤ ≤0.3.0enisa_euvdEU
jwt-simple project jwt-simple≤ 0.3.0nvdUScpe:2.3:a:jwt-simple_project:jwt-simple:*:*:*:*:*:*:*:*
npm jwt-simple< 0.3.1osvUSpkg:npm/jwt-simple

advisories (1)

Vendor and ecosystem advisories describing this.

GHSA-vgrx-w6rg-8fqfForgeable Public/Private Tokens in jwt-simple2018-11-06ghsa · osvUS
Affected versions of the `jwt-simple` package allow users to select what algorithm the server will use to verify a provided JWT. A malicious actor can use this behaviour to arbitrarily modify the contents of a JWT while still passing verification. For the common use case of the JWT, the end result is a complete authentication bypass with minimal effort. ## Recommendation Update to version 0.3.1 or later. Additionally, be sure to always specify an algorithm in calls to `.decode()`.

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd osv NVD CVE.org MITRE

published 2018-05-31modified 2026-06-17

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references (12)

External citations — patches, advisories, analysis.

scry

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