# CVE-2016-9123: Integer Overflow in go-jose

> An integer overflow in CBC-HMAC processing on 32-bit systems allows attackers to bypass authentication for encrypted ciphertexts.

- **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:** 28 Mar 2017
- **Updated:** 6 Aug 2024
- **Also known as:** DEBIAN-CVE-2016-9123, GHSA-3fx4-7f69-5mmg, GO-2020-0009

## What is CVE-2016-9123?

CVE-2016-9123 is a high-severity vulnerability in Go JOSE All versions before 1.0.5, published on 28 Mar 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

go-jose before 1.0.5 suffers from a CBC-HMAC integer overflow on 32-bit architectures. An integer overflow could lead to authentication bypass for CBC-HMAC encrypted ciphertexts on 32-bit architectures.

Weakness: CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2016-9123?

3 open source packages ship an affected version, including github.com/square/go-jose. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/square/go-jose` | Go | All versions | 0.0.0-20160903044734-789a4c4bd4c1 |
| `github.com/square/go-jose` | Go | All versions | 0.0.0-20160903044734-789a4c4bd4c1 |
| `github.com/square/go-jose` | Go | All versions | 0.0.0-20160903044734-789a4c4bd4c1 |

Products: Go-Jose Project Go-Jose.

## How do I fix CVE-2016-9123?

Upgrade github.com/square/go-jose to 0.0.0-20160903044734-789a4c4bd4c1 or later.

## Is CVE-2016-9123 being exploited?

There is no known exploitation of CVE-2016-9123 in the wild and no public exploit code.

## Other vulnerabilities in Go JOSE All versions before 1.0.5

- [CVE-2016-9121](https://insights.sbomify.com/CVE-2016-9121/): Elliptic Curve Key Disclosure in go-jose (critical 9.1)
- [CVE-2026-34986](https://insights.sbomify.com/CVE-2026-34986/): Go JOSE affect by a panic in JWE decryption (high 7.5)
- [CVE-2016-9122](https://insights.sbomify.com/CVE-2016-9122/): Go JOSE Signature Validation Bypass (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-9123 and fix it if it is affected.

What it is: CVE-2016-9123 is a high-severity vulnerability in Go JOSE All versions before 1.0.5, published on 28 Mar 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-2016-9123 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/square/go-jose (Go): affected all versions; fixed in 0.0.0-20160903044734-789a4c4bd4c1
- github.com/square/go-jose (Go): affected all versions; fixed in 0.0.0-20160903044734-789a4c4bd4c1
- github.com/square/go-jose (Go): affected all versions; fixed in 0.0.0-20160903044734-789a4c4bd4c1

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-2016-9123/ (Markdown: https://insights.sbomify.com/CVE-2016-9123/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-9123
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-9123
- OSV: https://osv.dev/vulnerability/CVE-2016-9123

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From sbomify Insights: https://insights.sbomify.com/CVE-2016-9123/
Summaries are generated and may contain mistakes; the official description above is the record.