# CVE-2020-36563: Weak hash (SHA-1) in github.com/RobotsAndPencils/go-saml

> Attackers can exploit SHA-1 hash collisions in XML Digital Signatures to bypass authentication in applications using this Go SAML library.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 27 Dec 2022
- **Updated:** 11 Apr 2025
- **Also known as:** GHSA-5rhg-xhgr-5hfj, GO-2020-0047

## What is CVE-2020-36563?

CVE-2020-36563 is a medium-severity vulnerability in github.com/RobotsAndPencils/go-saml, published on 27 Dec 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

XML Digital Signatures generated and validated using this package use SHA-1, which may allow an attacker to craft inputs which cause hash collisions depending on their control over the input.

Weakness: CWE-347 (Improper Verification of Cryptographic Signature)

## Which versions are affected by CVE-2020-36563?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/RobotsAndPencils/go-saml` | Go | All versions | None |
| `github.com/RobotsAndPencils/go-saml` | Go | All versions to 0.0.0-20170520135329-fb13cb52a46b | None |
| `github.com/RobotsAndPencils/go-saml` | Go | All versions to 0.0.0-20170520135329-fb13cb52a46b | None |

Products: Robotsandpencils Go-Saml.

## How do I fix CVE-2020-36563?

No fix has been published for CVE-2020-36563 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-36563 being exploited?

There is no known exploitation of CVE-2020-36563 in the wild and no public exploit code.

## Other vulnerabilities in github.com/RobotsAndPencils/go-saml

- [CVE-2023-48703](https://insights.sbomify.com/CVE-2023-48703/): SAML authentication bypass vulnerability in RobotsAndPencils/go-saml (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-36563 and fix it if it is affected.

What it is: CVE-2020-36563 is a medium-severity vulnerability in github.com/RobotsAndPencils/go-saml, published on 27 Dec 2022. 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-2020-36563 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/RobotsAndPencils/go-saml (Go): affected all versions; no fix listed
- github.com/RobotsAndPencils/go-saml (Go): affected all versions up to 0.0.0-20170520135329-fb13cb52a46b; no fix listed
- github.com/RobotsAndPencils/go-saml (Go): affected all versions up to 0.0.0-20170520135329-fb13cb52a46b; no fix listed

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-2020-36563/ (Markdown: https://insights.sbomify.com/CVE-2020-36563/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-36563
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-36563
- OSV: https://osv.dev/vulnerability/CVE-2020-36563

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-36563/
Summaries are generated and may contain mistakes; the official description above is the record.