# CVE-2017-12972: Nimbus JOSE+JWT missing overflow check

> Attackers can bypass HMAC verification in Nimbus JOSE+JWT by exploiting an integer overflow during length conversion, allowing them to forge valid tokens.

- **Severity:** High 7.5 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 20 Aug 2017
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-2qp9-wg27-9pcv

## What is CVE-2017-12972?

CVE-2017-12972 is a high-severity vulnerability in n/a, published on 20 Aug 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-345 (Insufficient Verification of Data Authenticity)

## Which versions are affected by CVE-2017-12972?

2 open source packages ship an affected version, including com.nimbusds:nimbus-jose-jwt. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `com.nimbusds:nimbus-jose-jwt` | Maven | All versions | 4.39 |
| `com.nimbusds:nimbus-jose-jwt` | Maven | All versions | 4.39 |

Products: Connect2id Nimbus Jose\+jwt.

## How do I fix CVE-2017-12972?

Upgrade com.nimbusds:nimbus-jose-jwt to 4.39 or later.

## Is CVE-2017-12972 being exploited?

There is no known exploitation of CVE-2017-12972 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2023-52428](https://insights.sbomify.com/CVE-2023-52428/): Denial of Service in Connect2id Nimbus JOSE+JWT (high 7.5)
- [CVE-2017-12974](https://insights.sbomify.com/CVE-2017-12974/): Improper Verification of Cryptographic Signature in Nimbus JOSE+JWT (high 7.5)
- [CVE-2017-12973](https://insights.sbomify.com/CVE-2017-12973/): Nimbus JOSE+JWT vulnerable to padding oracle attack (low 3.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-12972 and fix it if it is affected.

What it is: CVE-2017-12972 is a high-severity vulnerability in n/a, published on 20 Aug 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2017-12972 in the wild and no public exploit code.

Affected packages and fixed versions:
- com.nimbusds:nimbus-jose-jwt (Maven): affected all versions; fixed in 4.39
- com.nimbusds:nimbus-jose-jwt (Maven): affected all versions; fixed in 4.39

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2017-12972/ (Markdown: https://insights.sbomify.com/CVE-2017-12972/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-12972
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-12972
- OSV: https://osv.dev/vulnerability/CVE-2017-12972

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-12972/
Summaries are generated and may contain mistakes; the official description above is the record.