diff --git a/__tests__/distributors/base-installer.test.ts b/__tests__/distributors/base-installer.test.ts
index 281f73e5e..c4512ea90 100644
--- a/__tests__/distributors/base-installer.test.ts
+++ b/__tests__/distributors/base-installer.test.ts
@@ -1758,6 +1758,9 @@ describe('normalizeVersion', () => {
     ['11.0.9.1', {version: '11.0.9+1', stable: true, latest: false}],
     ['12.0.2.1.0', {version: '12.0.2+1.0', stable: true, latest: false}],
     ['18.0.1.1-ea', {version: '18.0.1+1', stable: false, latest: false}],
+    ['26.0.2.1+1', {version: '26.0.2+1.1', stable: true, latest: false}],
+    ['25.0.4.1+1', {version: '25.0.4+1.1', stable: true, latest: false}],
+    ['26.0.2+10', {version: '26.0.2+10', stable: true, latest: false}],
     ['latest', {version: 'x', stable: true, latest: true}],
     ['LATEST', {version: 'x', stable: true, latest: true}],
     ['  Latest  ', {version: 'x', stable: true, latest: true}]
diff --git a/__tests__/util.test.ts b/__tests__/util.test.ts
index 97f932fbb..c4bf99afd 100644
--- a/__tests__/util.test.ts
+++ b/__tests__/util.test.ts
@@ -181,7 +181,10 @@ describe('convertVersionToSemver', () => {
     ['12.0', '12.0'],
     ['12.0.2', '12.0.2'],
     ['12.0.2.1', '12.0.2+1'],
-    ['12.0.2.1.0', '12.0.2+1.0']
+    ['12.0.2.1.0', '12.0.2+1.0'],
+    ['26.0.2.1+1', '26.0.2+1.1'],
+    ['25.0.4.1+1', '25.0.4+1.1'],
+    ['26.0.2+10', '26.0.2+10']
   ])('%s -> %s', (input: string, expected: string) => {
     const actual = convertVersionToSemver(input);
     expect(actual).toBe(expected);
diff --git a/dist/cleanup/index.js b/dist/cleanup/index.js
index 00ad7724f..5c1988213 100644
--- a/dist/cleanup/index.js
+++ b/dist/cleanup/index.js
@@ -31239,13 +31239,28 @@ function avoidOldNotation(content) {
     return content.startsWith('1.') ? content.substring(2) : content;
 }
 function convertVersionToSemver(version) {
-    // Some distributions may use semver-like notation (12.10.2.1, 12.10.2.1.1)
-    const versionArray = Array.isArray(version) ? version : version.split('.');
+    // Some distributions may use semver-like notation (12.10.2.1, 12.10.2.1.1).
+    // Temurin also publishes four-field versions that already carry build
+    // metadata (26.0.2.1+1). Preserve that +build by folding the extra numeric
+    // fields into SemVer build metadata alongside it.
+    if (Array.isArray(version)) {
+        const mainVersion = version.slice(0, 3).join('.');
+        if (version.length > 3) {
+            return `${mainVersion}+${version.slice(3).join('.')}`;
+        }
+        return mainVersion;
+    }
+    const plusIndex = version.indexOf('+');
+    const core = plusIndex >= 0 ? version.slice(0, plusIndex) : version;
+    const existingBuild = plusIndex >= 0 ? version.slice(plusIndex + 1) : '';
+    const versionArray = core.split('.');
     const mainVersion = versionArray.slice(0, 3).join('.');
     if (versionArray.length > 3) {
-        return `${mainVersion}+${versionArray.slice(3).join('.')}`;
+        const fromFields = versionArray.slice(3).join('.');
+        const mergedBuild = [fromFields, existingBuild].filter(Boolean).join('.');
+        return `${mainVersion}+${mergedBuild}`;
     }
-    return mainVersion;
+    return existingBuild ? `${mainVersion}+${existingBuild}` : mainVersion;
 }
 /**
  * Builds a validator for the bytes currently served by a URL from the response
diff --git a/dist/setup/242.index.js b/dist/setup/242.index.js
index 12e3d457d..0fc815fb6 100644
--- a/dist/setup/242.index.js
+++ b/dist/setup/242.index.js
@@ -731,9 +731,10 @@ class JavaBase {
         // Java uses a versioning scheme (JEP 322) that can contain more numeric
         // fields than SemVer allows, e.g. '18.0.1.1' or '11.0.9.1'. Convert such
         // exact versions to SemVer build notation ('18.0.1+1') so they are
-        // accepted. Ranges and versions that already carry build metadata are
-        // left untouched.
-        if (/^\d+(\.\d+){3,}$/.test(version)) {
+        // accepted. Also cover four-field versions that already include +build
+        // metadata (Temurin: '26.0.2.1+1' -> '26.0.2+1.1'). Ranges with fewer
+        // than four numeric fields are left untouched.
+        if (/^\d+(\.\d+){3,}(\+.*)?$/.test(version)) {
             version = (0,util/* convertVersionToSemver */.ZY)(version);
         }
         if (!semver_default().validRange(version)) {
diff --git a/dist/setup/index.js b/dist/setup/index.js
index 8e019a02a..d4413fe30 100644
--- a/dist/setup/index.js
+++ b/dist/setup/index.js
@@ -31696,13 +31696,28 @@ function avoidOldNotation(content) {
     return content.startsWith('1.') ? content.substring(2) : content;
 }
 function convertVersionToSemver(version) {
-    // Some distributions may use semver-like notation (12.10.2.1, 12.10.2.1.1)
-    const versionArray = Array.isArray(version) ? version : version.split('.');
+    // Some distributions may use semver-like notation (12.10.2.1, 12.10.2.1.1).
+    // Temurin also publishes four-field versions that already carry build
+    // metadata (26.0.2.1+1). Preserve that +build by folding the extra numeric
+    // fields into SemVer build metadata alongside it.
+    if (Array.isArray(version)) {
+        const mainVersion = version.slice(0, 3).join('.');
+        if (version.length > 3) {
+            return `${mainVersion}+${version.slice(3).join('.')}`;
+        }
+        return mainVersion;
+    }
+    const plusIndex = version.indexOf('+');
+    const core = plusIndex >= 0 ? version.slice(0, plusIndex) : version;
+    const existingBuild = plusIndex >= 0 ? version.slice(plusIndex + 1) : '';
+    const versionArray = core.split('.');
     const mainVersion = versionArray.slice(0, 3).join('.');
     if (versionArray.length > 3) {
-        return `${mainVersion}+${versionArray.slice(3).join('.')}`;
+        const fromFields = versionArray.slice(3).join('.');
+        const mergedBuild = [fromFields, existingBuild].filter(Boolean).join('.');
+        return `${mainVersion}+${mergedBuild}`;
     }
-    return mainVersion;
+    return existingBuild ? `${mainVersion}+${existingBuild}` : mainVersion;
 }
 /**
  * Builds a validator for the bytes currently served by a URL from the response
diff --git a/src/distributions/base-installer.ts b/src/distributions/base-installer.ts
index f2d0c1414..65f5b9964 100644
--- a/src/distributions/base-installer.ts
+++ b/src/distributions/base-installer.ts
@@ -676,9 +676,10 @@ export abstract class JavaBase {
     // Java uses a versioning scheme (JEP 322) that can contain more numeric
     // fields than SemVer allows, e.g. '18.0.1.1' or '11.0.9.1'. Convert such
     // exact versions to SemVer build notation ('18.0.1+1') so they are
-    // accepted. Ranges and versions that already carry build metadata are
-    // left untouched.
-    if (/^\d+(\.\d+){3,}$/.test(version)) {
+    // accepted. Also cover four-field versions that already include +build
+    // metadata (Temurin: '26.0.2.1+1' -> '26.0.2+1.1'). Ranges with fewer
+    // than four numeric fields are left untouched.
+    if (/^\d+(\.\d+){3,}(\+.*)?$/.test(version)) {
       version = convertVersionToSemver(version);
     }
 
diff --git a/src/util.ts b/src/util.ts
index e2583849d..776694da6 100644
--- a/src/util.ts
+++ b/src/util.ts
@@ -501,13 +501,29 @@ function avoidOldNotation(content: string): string {
 }
 
 export function convertVersionToSemver(version: number[] | string) {
-  // Some distributions may use semver-like notation (12.10.2.1, 12.10.2.1.1)
-  const versionArray = Array.isArray(version) ? version : version.split('.');
+  // Some distributions may use semver-like notation (12.10.2.1, 12.10.2.1.1).
+  // Temurin also publishes four-field versions that already carry build
+  // metadata (26.0.2.1+1). Preserve that +build by folding the extra numeric
+  // fields into SemVer build metadata alongside it.
+  if (Array.isArray(version)) {
+    const mainVersion = version.slice(0, 3).join('.');
+    if (version.length > 3) {
+      return `${mainVersion}+${version.slice(3).join('.')}`;
+    }
+    return mainVersion;
+  }
+
+  const plusIndex = version.indexOf('+');
+  const core = plusIndex >= 0 ? version.slice(0, plusIndex) : version;
+  const existingBuild = plusIndex >= 0 ? version.slice(plusIndex + 1) : '';
+  const versionArray = core.split('.');
   const mainVersion = versionArray.slice(0, 3).join('.');
   if (versionArray.length > 3) {
-    return `${mainVersion}+${versionArray.slice(3).join('.')}`;
+    const fromFields = versionArray.slice(3).join('.');
+    const mergedBuild = [fromFields, existingBuild].filter(Boolean).join('.');
+    return `${mainVersion}+${mergedBuild}`;
   }
-  return mainVersion;
+  return existingBuild ? `${mainVersion}+${existingBuild}` : mainVersion;
 }
 
 /**