diff --git a/loader/goroot.go b/loader/goroot.go
index 12b797627..df4ae40cf 100644
--- a/loader/goroot.go
+++ b/loader/goroot.go
@@ -268,6 +268,16 @@ func pathsToOverride(goMinor int, needsSyscallPackage bool) map[string]bool {
 		paths["crypto/internal/boring/sig/"] = false
 	}
 
+	if goMinor >= 26 {
+		// Go 1.26 added a CPU jitter entropy source for FIPS 140-3 that
+		// allocates a 32 MiB global buffer (ScratchBuffer [1<<25]byte).
+		// This is fine on systems with virtual memory, but causes RAM
+		// overflow on microcontrollers. Replace with a zero-size stub
+		// since TinyGo targets never use FIPS jitter entropy.
+		paths["crypto/internal/entropy/"] = true
+		paths["crypto/internal/entropy/v1.0.0/"] = false
+	}
+
 	if needsSyscallPackage {
 		paths["syscall/"] = true // include syscall/js
 		paths["internal/syscall/"] = true
diff --git a/src/crypto/internal/entropy/v1.0.0/entropy.go b/src/crypto/internal/entropy/v1.0.0/entropy.go
new file mode 100644
index 000000000..eeeaf2158
--- /dev/null
+++ b/src/crypto/internal/entropy/v1.0.0/entropy.go
@@ -0,0 +1,56 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Stripped-down version of the entropy package for TinyGo.
+//
+// The upstream Go 1.26 package allocates a [1<<25]byte (32 MiB) global buffer
+// for CPU jitter-based SP 800-90B entropy collection. This is fine on systems
+// with virtual memory where BSS pages are lazily backed, but it causes a fatal
+// "RAM overflowed" error on microcontrollers and other memory-constrained
+// targets.
+//
+// Because FIPS 140-3 jitter entropy is never used on TinyGo targets (the DRBG
+// falls through to sysrand.Read when fips140.Enabled is false), this overlay
+// replaces the 32 MiB buffer with a zero-size type.
+package entropy
+
+// Version returns the version of the entropy source.
+func Version() string {
+	return "v1.0.0"
+}
+
+// ScratchBuffer is a large buffer in upstream Go (32 MiB). TinyGo replaces it
+// with a zero-size type since the CPU jitter entropy source is not used.
+type ScratchBuffer [0]byte
+
+// Seed returns a 384-bit seed with full entropy.
+// On TinyGo targets this is never called because FIPS mode is not enabled.
+func Seed(memory *ScratchBuffer) ([48]byte, error) {
+	panic("entropy: CPU jitter entropy source is not supported on TinyGo targets")
+}
+
+// Samples collects entropy samples. Not supported on TinyGo targets.
+func Samples(samples []uint8, memory *ScratchBuffer) error {
+	panic("entropy: CPU jitter entropy source is not supported on TinyGo targets")
+}
+
+// SHA384 computes SHA-384 over 1024 bytes. Not supported on TinyGo targets.
+func SHA384(p *[1024]byte) [48]byte {
+	panic("entropy: CPU jitter entropy source is not supported on TinyGo targets")
+}
+
+// TestingOnlySHA384 computes SHA-384 over arbitrary bytes. Not supported on TinyGo targets.
+func TestingOnlySHA384(p []byte) [48]byte {
+	panic("entropy: CPU jitter entropy source is not supported on TinyGo targets")
+}
+
+// RepetitionCountTest implements the repetition count test from SP 800-90B.
+func RepetitionCountTest(samples []uint8) error {
+	panic("entropy: CPU jitter entropy source is not supported on TinyGo targets")
+}
+
+// AdaptiveProportionTest implements the adaptive proportion test from SP 800-90B.
+func AdaptiveProportionTest(samples []uint8) error {
+	panic("entropy: CPU jitter entropy source is not supported on TinyGo targets")
+}