diff --git a/src/tests/gl_tests/PbufferTest.cpp b/src/tests/gl_tests/PbufferTest.cpp
--- a/src/tests/gl_tests/PbufferTest.cpp
+++ b/src/tests/gl_tests/PbufferTest.cpp
@@ -1249,8 +1249,68 @@
     eglDestroySurface(display, pbufferSurface);
 }

+// ES3 fixture so that GL_TEXTURE_BASE_LEVEL is accepted by validation.
+class PbufferBaseLevelTestES3 : public PbufferTest
+{};
+
+// Regression test: setting GL_TEXTURE_BASE_LEVEL > 0 on a pbuffer-bound
+// (non-immutable) GL_TEXTURE_2D must not pass an out-of-range mip NSRange to
+// -[MTLTexture newTextureViewWithPixelFormat:textureType:levels:slices:].
+//
+// Preconditions on the Metal backend:
+//   - eglBindTexImage -> TextureMtl::bindTexImage sets mBoundSurface and a
+//     1-mip mNativeTextureStorage with baseGLLevel=0.
+//   - The texture is not immutable, so getEffectiveBaseLevel() == mBaseLevel.
+//   - onBaseMaxLevelsChanged takes the isImmutableOrPBuffer() short path and
+//     calls createViewFromBaseToMaxLevel() without rebuilding storage.
+//
+// With baseLevel=5 and a 1-mip storage (getMaxSupportedGLLevel()==0),
+// createViewFromBaseToMaxLevel() computes maxLevel=max(min(0,..),5)=5,
+// baseToMaxLevels=1, then calls createMipsView(5,1) ->
+// [parent newTextureView... levels:NSMakeRange(5,1)] on a parent with
+// mipmapLevelCount==1. With Metal API validation enabled (MTL_DEBUG_LAYER=1)
+// this asserts; in release it is driver-level UB.
+TEST_P(PbufferBaseLevelTestES3, BaseLevelGreaterThanPbufferMipCount)
+{
+    ANGLE_SKIP_TEST_IF(!mSupportsPbuffers || !mSupportsBindTexImage);
+    ANGLE_SKIP_TEST_IF(getClientMajorVersion() < 3);
+
+    EGLWindow *window = getEGLWindow();
+
+    GLTexture texture;
+    glBindTexture(GL_TEXTURE_2D, texture);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+    EXPECT_GL_NO_ERROR();
+
+    // Bind the 1-mip pbuffer surface to the texture (non-immutable).
+    EXPECT_EGL_TRUE(eglBindTexImage(window->getDisplay(), mPbuffer, EGL_BACK_BUFFER));
+    glViewport(0, 0, getWindowWidth(), getWindowHeight());
+    EXPECT_GL_NO_ERROR();
+
+    // Trigger TextureMtl::onBaseMaxLevelsChanged -> createViewFromBaseToMaxLevel
+    // with EffectiveBaseLevel(5) > getMaxSupportedGLLevel(0).
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 5);
+    EXPECT_GL_NO_ERROR();
+
+    // Exercise the resulting view: sample it from a fragment shader so that the
+    // (potentially out-of-range) MTLTexture view is bound to a render encoder.
+    glUseProgram(mTextureProgram);
+    glUniform1i(mTextureUniformLocation, 0);
+    drawQuad(mTextureProgram, "position", 0.5f);
+    glFinish();
+    EXPECT_GL_NO_ERROR();
+
+    // Restore and release.
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 0);
+    eglReleaseTexImage(window->getDisplay(), mPbuffer, EGL_BACK_BUFFER);
+}
+
 ANGLE_INSTANTIATE_TEST_ES2(PbufferTest);

+GTEST_ALLOW_UNINSTANTIATED_PARAMETERIZED_TEST(PbufferBaseLevelTestES3);
+ANGLE_INSTANTIATE_TEST_ES3(PbufferBaseLevelTestES3);
+
 GTEST_ALLOW_UNINSTANTIATED_PARAMETERIZED_TEST(PbufferColorspaceTest);
 ANGLE_INSTANTIATE_TEST_ES3_AND(PbufferColorspaceTest,
                                ES3_VULKAN().enable(Feature::EglColorspaceAttributePassthrough));