How severe is GHSA-4j9m-h44m-2hv8?

GHSA-4j9m-h44m-2hv8 has a CVSS score of 1.9/10, rated LOW. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-4j9m-h44m-2hv8?

GHSA-4j9m-h44m-2hv8 affects the following packages: Steeltoe.Configuration.Encryption (NuGet). Ecosystems affected: NuGet.

How do I fix GHSA-4j9m-h44m-2hv8?

Update Steeltoe.Configuration.Encryption to 4.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4j9m-h44m-2hv8 is resolved across your whole dependency graph.

How do I detect GHSA-4j9m-h44m-2hv8 in my NuGet dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Steeltoe.Configuration.Encryption. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-4j9m-h44m-2hv8 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-4j9m-h44m-2hv8?

O3 pinpoints whether GHSA-4j9m-h44m-2hv8 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-4j9m-h44m-2hv8 actively exploited in the wild?

No public exploit code has been indexed for GHSA-4j9m-h44m-2hv8 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-4j9m-h44m-2hv8?

GHSA-4j9m-h44m-2hv8 has an EPSS (Exploit Prediction Scoring System) score of 0.0%, placing it in the 0th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-4j9m-h44m-2hv8?

GHSA-4j9m-h44m-2hv8 is classified as CWE-256 (CWE-256), Broken Cryptographic Algorithm (CWE-327). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-4j9m-h44m-2hv8 published, and has it been updated?

GHSA-4j9m-h44m-2hv8 was published on July 2, 2026 and was last updated on July 2, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

.NET NuGet

GHSA-4j9m-h44m-2hv8

LOW

Steeltoe: OAEP setting silently selects PKCS#1 v1.5 padding

Also known asCVE-2026-50268

Published

Jul 2, 2026

Updated

Jul 2, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

0.0%probability of exploitation in next 30 days

Lower Risk0th percentile+0.00%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

.NETSteeltoe.Configuration.Encryption

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.

Description

Summary

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.

Impact

Operators who configure encrypt:rsa:algorithm=OAEP to obtain CCA2-secure padding receive PKCS#1 v1.5 instead. Currently, Decrypt() is called only against operator-controlled configuration data, so no exploitable path exists, but any future code path that exposes a decryption oracle would be Bleichenbacher-vulnerable despite the OAEP setting.

Migration note

Existing {cipher} values produced under the broken OAEP setting were encrypted with PKCS#1 v1.5. The fix makes OAEP use actual OAEP padding, so those values will fail to decrypt after upgrading. Re-encrypt all affected {cipher} values after upgrading.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
.NETNuGet	`Steeltoe.Configuration.Encryption`	≥ 4.0.0&&< 4.2.0	4.2.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Steeltoe.Configuration.Encryption. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update Steeltoe.Configuration.Encryption to 4.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4j9m-h44m-2hv8 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-4j9m-h44m-2hv8 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-4j9m-h44m-2hv8. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Summary 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. ### Impact Operators who configure `encrypt:rsa:algorithm=OAEP` to obtain CCA2-secure padding receive PKCS#1 v1.5 instead. Currently, `Decrypt()` is called only against operator-controlled configuration data, so no exploitable path exists, but any future code path that exposes a decryption oracle would be Bleichenbacher-vulnerable despite the `OAEP` setting.

O3 Security · Impact-Aware SCA

Is GHSA-4j9m-h44m-2hv8 in your dependencies?

O3 detects GHSA-4j9m-h44m-2hv8 across NuGet dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works