diff --git a/src/Renci.SshNet/PrivateKeyFile.cs b/src/Renci.SshNet/PrivateKeyFile.cs
index c7b9ccbc9..018d68cbf 100644
--- a/src/Renci.SshNet/PrivateKeyFile.cs
+++ b/src/Renci.SshNet/PrivateKeyFile.cs
@@ -110,18 +110,23 @@ namespace Renci.SshNet
     /// </remarks>
     public partial class PrivateKeyFile : IPrivateKeySource, IDisposable
     {
-        private const string PrivateKeyPattern = @"^-+ *BEGIN (?<keyName>\w+( \w+)*) *-+\r?\n((Proc-Type: 4,ENCRYPTED\r?\nDEK-Info: (?<cipherName>[A-Z0-9-]+),(?<salt>[a-fA-F0-9]+)\r?\n\r?\n)|(Comment: ""?[^\r\n]*""?\r?\n))?(?<data>([a-zA-Z0-9/+=]{1,80}\r?\n)+)(\r?\n)?-+ *END \k<keyName> *-+";
+        private const string PrivateKeyPattern = @"^-+ *BEGIN (?<keyName>\w+( \w+)*) *-+[\r\n\t ]+((Proc-Type: 4,ENCRYPTED[\r\n\t ]+DEK-Info: (?<cipherName>[A-Z0-9-]+),(?<salt>[a-fA-F0-9]+)[\r\n\t ]+[\r\n\t ]+)|(Comment: ""?[^\r\n]*""?[\r\n\t ]+))?(?<data>[a-zA-Z0-9/+=\r\n\t ]+)([\r\n\t ]+)?-+ *END \k<keyName> *-+";
+        private const string InlinePrivateKeyPattern = @"^(?<begin>-+ *BEGIN (?<keyName>\w+( \w+)*) *-+)(?<data>[a-zA-Z0-9/+=]+)(?<end>-+ *END \k<keyName> *-+)$";
         private const string PuTTYPrivateKeyPattern = @"^(?<keyName>PuTTY-User-Key-File)-(?<version>\d+): (?<algorithmName>[\w-]+)\r?\nEncryption: (?<encryptionType>[\w-]+)\r?\nComment: (?<comment>.*?)\r?\nPublic-Lines: \d+\r?\n(?<publicKey>(([a-zA-Z0-9/+=]{1,64})\r?\n)+)(Key-Derivation: (?<argon2Type>\w+)\r?\nArgon2-Memory: (?<argon2Memory>\d+)\r?\nArgon2-Passes: (?<argon2Passes>\d+)\r?\nArgon2-Parallelism: (?<argon2Parallelism>\d+)\r?\nArgon2-Salt: (?<argon2Salt>[a-fA-F0-9]+)\r?\n)?Private-Lines: \d+\r?\n(?<data>(([a-zA-Z0-9/+=]{1,64})\r?\n)+)+Private-MAC: (?<mac>[a-fA-F0-9]+)";
         private const string CertificatePattern = @"(?<type>[-\w]+@openssh\.com)\s(?<data>[a-zA-Z0-9\/+=]*)(\s+(?<comment>.*))?";
 
 #if NET
         private static readonly Regex PrivateKeyRegex = GetPrivateKeyRegex();
+        private static readonly Regex InlinePrivateKeyRegex = GetInlinePrivateKeyRegex();
         private static readonly Regex PuTTYPrivateKeyRegex = GetPrivateKeyPuTTYRegex();
         private static readonly Regex CertificateRegex = GetCertificateRegex();
 
         [GeneratedRegex(PrivateKeyPattern, RegexOptions.Multiline | RegexOptions.ExplicitCapture)]
         private static partial Regex GetPrivateKeyRegex();
 
+        [GeneratedRegex(InlinePrivateKeyPattern, RegexOptions.ExplicitCapture)]
+        private static partial Regex GetInlinePrivateKeyRegex();
+
         [GeneratedRegex(PuTTYPrivateKeyPattern, RegexOptions.Multiline | RegexOptions.ExplicitCapture)]
         private static partial Regex GetPrivateKeyPuTTYRegex();
 
@@ -129,6 +134,7 @@ public partial class PrivateKeyFile : IPrivateKeySource, IDisposable
         private static partial Regex GetCertificateRegex();
 #else
         private static readonly Regex PrivateKeyRegex = new Regex(PrivateKeyPattern, RegexOptions.Compiled | RegexOptions.Multiline | RegexOptions.ExplicitCapture);
+        private static readonly Regex InlinePrivateKeyRegex = new Regex(InlinePrivateKeyPattern, RegexOptions.Compiled | RegexOptions.ExplicitCapture);
         private static readonly Regex PuTTYPrivateKeyRegex = new Regex(PuTTYPrivateKeyPattern, RegexOptions.Compiled | RegexOptions.Multiline | RegexOptions.ExplicitCapture);
         private static readonly Regex CertificateRegex = new Regex(CertificatePattern, RegexOptions.Compiled | RegexOptions.ExplicitCapture);
 #endif
@@ -292,7 +298,7 @@ private void Open(Stream privateKey, string? passPhrase)
 
             using (var sr = new StreamReader(privateKey))
             {
-                var text = sr.ReadToEnd();
+                var text = NormalizeInlinePrivateKey(sr.ReadToEnd());
                 if (text.StartsWith("PuTTY-User-Key-File", StringComparison.Ordinal))
                 {
                     privateKeyMatch = PuTTYPrivateKeyRegex.Match(text);
@@ -379,6 +385,27 @@ private void Open(Stream privateKey, string? passPhrase)
             }
         }
 
+        private static string NormalizeInlinePrivateKey(string text)
+        {
+            if (text.IndexOfAny(['\r', '\n']) >= 0)
+            {
+                return text;
+            }
+
+            var privateKeyMatch = InlinePrivateKeyRegex.Match(text.Trim());
+            if (!privateKeyMatch.Success)
+            {
+                return text;
+            }
+
+            return string.Concat(
+                privateKeyMatch.Groups["begin"].Value,
+                "\n",
+                privateKeyMatch.Groups["data"].Value,
+                "\n",
+                privateKeyMatch.Groups["end"].Value);
+        }
+
         /// <summary>
         /// Opens the specified certificate.
         /// </summary>
diff --git a/test/Renci.SshNet.Tests/Classes/PrivateKeyFileTest.cs b/test/Renci.SshNet.Tests/Classes/PrivateKeyFileTest.cs
index f18cef76e..4f0b5a3e4 100644
--- a/test/Renci.SshNet.Tests/Classes/PrivateKeyFileTest.cs
+++ b/test/Renci.SshNet.Tests/Classes/PrivateKeyFileTest.cs
@@ -3,6 +3,7 @@
 using System.IO;
 using System.Linq;
 using System.Text;
+using System.Text.RegularExpressions;
 
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 
@@ -609,6 +610,40 @@ public void PuTTYv3_InvalidMac_ThrowsSshException()
             }
         }
 
+        [TestMethod]
+        [DataRow("Key.RSA.PKCS8.txt", null, typeof(RsaKey))]
+        [DataRow("Key.OPENSSH.RSA.txt", null, typeof(RsaKey))]
+        [DataRow("Key.RSA.txt", null, typeof(RsaKey))]
+        [DataRow("Key.ECDSA.txt", null, typeof(EcdsaKey))]
+        [DataRow("Key.OPENSSH.ED25519.txt", null, typeof(ED25519Key))]
+        public void Test_PrivateKey_InlinePem_LineEndingsRemoved(string name, string passPhrase, Type expectedKeyType)
+        {
+            // Simulate CI/CD environment variable injection (e.g. Azure DevOps) where
+            // the PEM line endings are removed, producing an inline single-line key.
+            string original;
+            using (var stream = GetData(name))
+            using (var reader = new StreamReader(stream))
+            {
+                original = reader.ReadToEnd();
+            }
+
+            // Remove all line endings to produce the inline format,
+            // matching what CI/CD systems (e.g. Azure DevOps) produce when injecting secrets.
+            var inlinePem = Regex.Replace(original, @"\r\n?|\n", string.Empty).Trim();
+
+            using (var stream = new MemoryStream(Encoding.UTF8.GetBytes(inlinePem)))
+            {
+                var pkFile = new PrivateKeyFile(stream, passPhrase);
+
+                Assert.IsInstanceOfType(pkFile.Key, expectedKeyType);
+
+                if (expectedKeyType == typeof(RsaKey))
+                {
+                    TestRsaKeyFile(pkFile);
+                }
+            }
+        }
+
         private void SaveStreamToFile(Stream stream, string fileName)
         {
             var buffer = new byte[4000];