{"id":"CVE-2026-50268","title":"Steeltoe: OAEP setting silently selects PKCS#1 v1.5 padding","summary":"Steeltoe: OAEP setting silently selects PKCS#1 v1.5 padding","severity":"low","cvss":1.9,"cwe":["CWE-256","CWE-327"],"vendor":"Steeltoe","product":"Steeltoe.Configuration.Encryption","ecosystem":"nuget","affected":["Steeltoe.Configuration.Encryption >= 4.0.0, <= 4.1.0"],"patched":["Steeltoe.Configuration.Encryption 4.2.0"],"published":"2026-07-02","updated":"2026-07-02","source":"GHSA","sourceUrl":"https://github.com/advisories/GHSA-4j9m-h44m-2hv8","references":[{"url":"https://github.com/SteeltoeOSS/security-advisories/security/advisories/GHSA-4j9m-h44m-2hv8"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-50268"},{"url":"https://github.com/SteeltoeOSS/Steeltoe/commit/6cfee5cccddf8f9a31de69b0ca5ccdd771b73e5b"},{"url":"https://github.com/advisories/GHSA-4j9m-h44m-2hv8"}],"tags":["ghsa","nuget"],"epss":0.00047,"epssPercentile":0,"ingestedAt":"2026-07-02T20:42:45.622Z","slug":"CVE-2026-50268","body":"## Overview\n\n### Summary\n\nConfiguring `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.\n\n### Impact\n\nOperators 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.\n\n### Migration note\n\nExisting `{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.\n\n## Affected packages\n\n- `Steeltoe.Configuration.Encryption >= 4.0.0, <= 4.1.0`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `Steeltoe.Configuration.Encryption 4.2.0`","depth":"sunlit","depthScore":10,"depthScoreParts":{"impact":10.5,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}