CVE-2016-10555
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...
- Published
- May 31, 2018
- Updated
- Sep 16, 2024
- Assigning CNA
- hackerone
- Evidence observed
- Aug 8, 2026
Primary CVSS
nvd · CVSS 3.0
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:NLow · next 30 days
- Percentile
- 91.6%
- Model date
- Sep 21, 2026
EPSS is a statistical estimate, not a certainty or a measure of impact. Combine it with CVSS, KEV status, exposure and your environment.
Summary
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.
Sources
2Change the algorithm RS256(asymmetric) to HS256(symmetric) - POC (CVE-2016-10555)
CVE-2016-10555 PoC code
Responsible use
Use vulnerability information only on systems you own or are authorized to test. Kitploit links to public research metadata and does not store exploit code or malicious payloads.