diff --git a/apps/components_tests/fx/lexer.cpp b/apps/components_tests/fx/lexer.cpp
index 976f88d7a3..f8996118da 100644
--- a/apps/components_tests/fx/lexer.cpp
+++ b/apps/components_tests/fx/lexer.cpp
@@ -135,6 +135,17 @@ namespace
         EXPECT_EQ(std::get<Integer>(token).value, 123);
     }
 
+    TEST(LexerTest, float_suffix_should_be_float)
+    {
+        Lexer lexer(R"(
+            123f
+        )");
+
+        auto token = lexer.next();
+        EXPECT_TRUE(std::holds_alternative<Float>(token));
+        EXPECT_FLOAT_EQ(std::get<Float>(token).value, 123.f);
+    }
+
     TEST(LexerTest, simple_string)
     {
         Lexer lexer(R"(
diff --git a/apps/components_tests/fx/technique.cpp b/apps/components_tests/fx/technique.cpp
index b04ff5c52a..63d65ef95f 100644
--- a/apps/components_tests/fx/technique.cpp
+++ b/apps/components_tests/fx/technique.cpp
@@ -90,6 +90,56 @@ namespace
     technique { passes = main; }
 )" };
 
+    constexpr VFS::Path::NormalizedView invalidNumberInfPath("shaders/invalid_number_inf.omwfx");
+
+    TestingOpenMW::VFSTestFile invalidNumberInf{ R"(
+    uniform_vec4 uVec4 {
+        step = inf;
+    }
+    fragment main { }
+    technique { passes = main; }
+)" };
+
+    constexpr VFS::Path::NormalizedView invalidNumberNegativeInfPath("shaders/invalid_number_negative_inf.omwfx");
+
+    TestingOpenMW::VFSTestFile invalidNumberNegativeInf{ R"(
+    uniform_vec4 uVec4 {
+        step = -inf;
+    }
+    fragment main { }
+    technique { passes = main; }
+)" };
+
+    constexpr VFS::Path::NormalizedView invalidNumberUnsignedLongPath("shaders/invalid_number_ulong.omwfx");
+
+    TestingOpenMW::VFSTestFile invalidNumberUnsignedLong{ R"(
+    uniform_vec4 uVec4 {
+        step = 18446744073709551615;
+    }
+    fragment main { }
+    technique { passes = main; }
+)" };
+
+    constexpr VFS::Path::NormalizedView invalidNumberHexFloatPath("shaders/invalid_number_hex.omwfx");
+
+    TestingOpenMW::VFSTestFile invalidNumberHexFloat{ R"(
+    uniform_vec4 uVec4 {
+        step = 0x1.fffffep+12;
+    }
+    fragment main { }
+    technique { passes = main; }
+)" };
+
+    constexpr VFS::Path::NormalizedView invalidNumberDoublePath("shaders/invalid_number_double.omwfx");
+
+    TestingOpenMW::VFSTestFile invalidNumberDouble{ R"(
+    uniform_vec4 uVec4 {
+        step = 1.79769e+50;
+    }
+    fragment main { }
+    technique { passes = main; }
+)" };
+
     using namespace testing;
     using namespace Fx;
 
@@ -106,6 +156,11 @@ namespace
                 { uniformPropertiesPath, &uniformProperties },
                 { missingSamplerSourcePath, &missingSamplerSource },
                 { repeatedSharedBlockPath, &repeatedSharedBlock },
+                { invalidNumberInfPath, &invalidNumberInf },
+                { invalidNumberNegativeInfPath, &invalidNumberNegativeInf },
+                { invalidNumberUnsignedLongPath, &invalidNumberUnsignedLong },
+                { invalidNumberHexFloatPath, &invalidNumberHexFloat },
+                { invalidNumberDoublePath, &invalidNumberDouble },
             }))
             , mImageManager(mVFS.get(), 0)
         {
@@ -117,6 +172,17 @@ namespace
                 *mVFS.get(), mImageManager, Technique::makeFileName(name), name, 1, 1, true, true);
             mTechnique->compile();
         }
+
+        void expectFailure(const std::string& name, std::string_view errorString)
+        {
+            internal::CaptureStdout();
+
+            compile(name);
+
+            std::string output = internal::GetCapturedStdout();
+            Log(Debug::Error) << output;
+            EXPECT_THAT(output, HasSubstr(errorString));
+        }
     };
 
     TEST_F(TechniqueTest, technique_properties)
@@ -183,23 +249,24 @@ namespace
 
     TEST_F(TechniqueTest, fail_with_missing_source_for_sampler)
     {
-        internal::CaptureStdout();
-
-        compile("missing_sampler_source");
-
-        std::string output = internal::GetCapturedStdout();
-        Log(Debug::Error) << output;
-        EXPECT_THAT(output, HasSubstr("sampler_1d 'mysampler1d' requires a filename"));
+        expectFailure("missing_sampler_source", "sampler_1d 'mysampler1d' requires a filename");
     }
 
     TEST_F(TechniqueTest, fail_with_repeated_shared_block)
     {
-        internal::CaptureStdout();
+        expectFailure("repeated_shared_block", "repeated 'shared' block");
+    }
 
-        compile("repeated_shared_block");
+    TEST_F(TechniqueTest, fail_with_invalid_float)
+    {
+        expectFailure("invalid_number_inf", "expected float value");
+        expectFailure("invalid_number_negative_inf", "expected float value");
+        expectFailure("invalid_number_hex", "expected float value");
+    }
 
-        std::string output = internal::GetCapturedStdout();
-        Log(Debug::Error) << output;
-        EXPECT_THAT(output, HasSubstr("repeated 'shared' block"));
+    TEST_F(TechniqueTest, fail_with_out_of_range)
+    {
+        expectFailure("invalid_number_ulong", "number out of range");
+        expectFailure("invalid_number_double", "number out of range");
     }
 }
diff --git a/components/fx/lexer.cpp b/components/fx/lexer.cpp
index 07d7f060a4..43ce17717f 100644
--- a/components/fx/lexer.cpp
+++ b/components/fx/lexer.cpp
@@ -1,13 +1,11 @@
 #include "lexer.hpp"
 
 #include <cctype>
+#include <cmath>
+#include <cstdlib>
 #include <format>
 
-#ifndef __cpp_lib_to_chars
-#include <cstdlib>
-#else
-#include <charconv>
-#endif
+#include <components/misc/strings/algorithm.hpp>
 
 namespace Fx
 {
@@ -294,23 +292,42 @@ namespace Fx
         Token Lexer::scanNumber()
         {
             double buffer;
-#ifndef __cpp_lib_to_chars
             char* endPtr = nullptr;
             buffer = std::strtod(mHead, &endPtr);
             if (endPtr == nullptr || endPtr == mHead)
-#else
-            const auto [endPtr, ec] = std::from_chars(mHead, mTail, buffer);
-            if (ec != std::errc())
-#endif
                 error("critical error while parsing number");
 
+            bool isDefinitelyAFloat = false;
+            // GLSL allows floats to end on f/F
+            if (endPtr != mTail && Misc::StringUtils::toLower(*endPtr) == 'f')
+            {
+                isDefinitelyAFloat = true;
+                ++endPtr;
+            }
+
             std::string_view literal(mHead, endPtr);
             mHead = endPtr;
 
-            if (literal.find('.') != std::string_view::npos)
-                return Float{ static_cast<float>(buffer) };
+            // Disallow -inf, -nan, and values that cannot be represented as doubles
+            if (!std::isfinite(buffer))
+                return Literal{ literal };
+            // Disallow hex notation (not allowed in GLSL so confusing to partially allow)
+            if (Misc::StringUtils::ciStartsWith(literal, "0x") || Misc::StringUtils::ciStartsWith(literal, "-0x"))
+                return Literal{ literal };
 
-            return Integer{ static_cast<int>(buffer) };
+            constexpr std::string_view floatCharacters = ".eE";
+            if (!isDefinitelyAFloat && literal.find_first_of(floatCharacters) == std::string_view::npos)
+            {
+                // This is supposed to be an int, but that doesn't mean it can fit in one
+                int intValue = static_cast<int>(buffer);
+                if (intValue != buffer)
+                    error("number out of range");
+                return Integer{ intValue };
+            }
+            float floatValue = static_cast<float>(buffer);
+            if (!std::isfinite(floatValue))
+                error("number out of range");
+            return Float{ floatValue };
         }
     }
 }
diff --git a/components/fx/technique.cpp b/components/fx/technique.cpp
index ac55a16b6f..945a3cf1b1 100644
--- a/components/fx/technique.cpp
+++ b/components/fx/technique.cpp
@@ -758,7 +758,7 @@ namespace Fx
 
         if (named)
         {
-            expect<Lexer::Literal>("name is required for preceeding block decleration");
+            expect<Lexer::Literal>("name is required for preceeding block declaration");
 
             mBlockName = std::get<Lexer::Literal>(mToken).value;