CVE-2017-12972

What it is

In Nimbus JOSE+JWT before 4.39, there is no integer-overflow check when converting length values from bytes to bits, which allows attackers to conduct HMAC bypass attacks by shifting Additional Authenticated Data (AAD) and ciphertext so that different plaintext is obtained for the same HMAC.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of data tampering.

Exploit odds

0.9% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2017-08-20 16:29 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 01:04 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.9% in the next 30 days (EPSS).
• Severity: 7.5 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2017-08-20 16:29 UTC

Last modified

2026-06-17 01:04 UTC

Exploit probability

0.9% · EPSS, next 30 days

Weakness

CWE-345

Record status

Modified

Affected

• connect2id Nimbus jose\+jwt 1.0
• connect2id Nimbus jose\+jwt 1.1
• connect2id Nimbus jose\+jwt 1.2
• connect2id Nimbus jose\+jwt 1.3
• connect2id Nimbus jose\+jwt 1.4
• connect2id Nimbus jose\+jwt 1.5
• connect2id Nimbus jose\+jwt 1.6
• connect2id Nimbus jose\+jwt 1.7

Attack profile CVSS 3.0 · 7.5

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

None

Is it in your code?

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