diff --git a/lib/common/pool.c b/lib/common/pool.c
index dd5fb0c4d4b..0177e3ccb22 100644
--- a/lib/common/pool.c
+++ b/lib/common/pool.c
@@ -117,7 +117,12 @@ POOL_ctx* POOL_create_advanced(size_t numThreads, size_t queueSize,
 {
     POOL_ctx* ctx;
     /* Check parameters */
-    if (!numThreads) { return NULL; }
+    if (!numThreads || numThreads > POOL_MAX_THREADS) {
+        return NULL;
+    }
+    if (queueSize >= (size_t)-1 / sizeof(POOL_job)) {
+        return NULL;
+    }
     /* Allocate the context and zero initialize */
     ctx = (POOL_ctx*)ZSTD_customCalloc(sizeof(POOL_ctx), customMem);
     if (!ctx) { return NULL; }
@@ -190,6 +195,7 @@ void POOL_free(POOL_ctx *ctx) {
  *  Waits for all queued jobs to finish executing.
  */
 void POOL_joinJobs(POOL_ctx* ctx) {
+    if (!ctx) { return; }
     ZSTD_pthread_mutex_lock(&ctx->queueMutex);
     while(!ctx->queueEmpty || ctx->numThreadsBusy > 0) {
         ZSTD_pthread_cond_wait(&ctx->queuePushCond, &ctx->queueMutex);
@@ -218,6 +224,7 @@ static int POOL_resize_internal(POOL_ctx* ctx, size_t numThreads)
         return 0;
     }
     /* numThreads > threadCapacity */
+    if (numThreads > POOL_MAX_THREADS) return 1;
     ctx->threadLimit = numThreads;
     {   ZSTD_pthread_t* const threadPool = (ZSTD_pthread_t*)ZSTD_customCalloc(numThreads * sizeof(ZSTD_pthread_t), ctx->customMem);
         if (!threadPool) return 1;
@@ -283,6 +290,7 @@ POOL_add_internal(POOL_ctx* ctx, POOL_function function, void *opaque)
 void POOL_add(POOL_ctx* ctx, POOL_function function, void* opaque)
 {
     assert(ctx != NULL);
+    assert(function != NULL);
     ZSTD_pthread_mutex_lock(&ctx->queueMutex);
     /* Wait until there is space in the queue for the new job */
     while (isQueueFull(ctx) && (!ctx->shutdown)) {
@@ -296,6 +304,7 @@ void POOL_add(POOL_ctx* ctx, POOL_function function, void* opaque)
 int POOL_tryAdd(POOL_ctx* ctx, POOL_function function, void* opaque)
 {
     assert(ctx != NULL);
+    assert(function != NULL);
     ZSTD_pthread_mutex_lock(&ctx->queueMutex);
     if (isQueueFull(ctx)) {
         ZSTD_pthread_mutex_unlock(&ctx->queueMutex);
@@ -350,11 +359,13 @@ int POOL_resize(POOL_ctx* ctx, size_t numThreads) {
 
 void POOL_add(POOL_ctx* ctx, POOL_function function, void* opaque) {
     (void)ctx;
+    assert(function != NULL);
     function(opaque);
 }
 
 int POOL_tryAdd(POOL_ctx* ctx, POOL_function function, void* opaque) {
     (void)ctx;
+    assert(function != NULL);
     function(opaque);
     return 1;
 }
diff --git a/lib/common/pool.h b/lib/common/pool.h
index f39b7f1eb99..d78da3e84d7 100644
--- a/lib/common/pool.h
+++ b/lib/common/pool.h
@@ -18,6 +18,8 @@
 
 typedef struct POOL_ctx_s POOL_ctx;
 
+#define POOL_MAX_THREADS 10000
+
 /*! POOL_create() :
  *  Create a thread pool with at most `numThreads` threads.
  * `numThreads` must be at least 1.
diff --git a/lib/compress/zstdmt_compress.c b/lib/compress/zstdmt_compress.c
index cb710475c2a..7b9a9be553e 100644
--- a/lib/compress/zstdmt_compress.c
+++ b/lib/compress/zstdmt_compress.c
@@ -143,10 +143,14 @@ static ZSTDMT_bufferPool* ZSTDMT_createBufferPool(unsigned maxNbBuffers, ZSTD_cu
 /* only works at initialization, not during compression */
 static size_t ZSTDMT_sizeof_bufferPool(ZSTDMT_bufferPool* bufPool)
 {
-    size_t const poolSize = sizeof(*bufPool);
-    size_t const arraySize = bufPool->totalBuffers * sizeof(Buffer);
+    size_t poolSize;
+    size_t arraySize;
     unsigned u;
     size_t totalBufferSize = 0;
+
+    if (bufPool == NULL) return 0;
+    poolSize = sizeof(*bufPool);
+    arraySize = bufPool->totalBuffers * sizeof(Buffer);
     ZSTD_pthread_mutex_lock(&bufPool->poolMutex);
     for (u=0; u<bufPool->totalBuffers; u++)
         totalBufferSize += bufPool->buffers[u].capacity;
@@ -161,6 +165,7 @@ static size_t ZSTDMT_sizeof_bufferPool(ZSTDMT_bufferPool* bufPool)
  * as they become freely interchangeable, reducing malloc/free usages and memory fragmentation */
 static void ZSTDMT_setBufferSize(ZSTDMT_bufferPool* const bufPool, size_t const bSize)
 {
+    if (bufPool == NULL) return;
     ZSTD_pthread_mutex_lock(&bufPool->poolMutex);
     DEBUGLOG(4, "ZSTDMT_setBufferSize: bSize = %u", (U32)bSize);
     bufPool->bufferSize = bSize;
@@ -417,6 +422,7 @@ static ZSTDMT_CCtxPool* ZSTDMT_expandCCtxPool(ZSTDMT_CCtxPool* srcPool,
 /* only works during initialization phase, not during compression */
 static size_t ZSTDMT_sizeof_CCtxPool(ZSTDMT_CCtxPool* cctxPool)
 {
+    if (cctxPool == NULL) return 0;
     ZSTD_pthread_mutex_lock(&cctxPool->poolMutex);
     {   unsigned const nbWorkers = cctxPool->totalCCtx;
         size_t const poolSize = sizeof(*cctxPool);
@@ -434,6 +440,7 @@ static size_t ZSTDMT_sizeof_CCtxPool(ZSTDMT_CCtxPool* cctxPool)
 
 static ZSTD_CCtx* ZSTDMT_getCCtx(ZSTDMT_CCtxPool* cctxPool)
 {
+    if (cctxPool == NULL) return NULL;
     DEBUGLOG(5, "ZSTDMT_getCCtx");
     ZSTD_pthread_mutex_lock(&cctxPool->poolMutex);
     if (cctxPool->availCCtx) {
@@ -449,7 +456,7 @@ static ZSTD_CCtx* ZSTDMT_getCCtx(ZSTDMT_CCtxPool* cctxPool)
 
 static void ZSTDMT_releaseCCtx(ZSTDMT_CCtxPool* pool, ZSTD_CCtx* cctx)
 {
-    if (cctx==NULL) return;   /* compatibility with release on NULL */
+    if (cctx==NULL || pool==NULL) return;
     ZSTD_pthread_mutex_lock(&pool->poolMutex);
     if (pool->availCCtx < pool->totalCCtx)
         pool->cctxs[pool->availCCtx++] = cctx;
diff --git a/tests/poolTests.c b/tests/poolTests.c
index 9e62722bfa0..50dc2de6591 100644
--- a/tests/poolTests.c
+++ b/tests/poolTests.c
@@ -233,6 +233,42 @@ int main(int argc, const char **argv) {
     return 1;
   }
 
+  if (POOL_create(1, (size_t)-1)) {
+    printf("FAIL: should not create POOL with overflowing queueSize\n");
+    return 1;
+  }
+
+  if (POOL_create((size_t)-1, 1)) {
+    printf("FAIL: should not create POOL with overflowing numThreads\n");
+    return 1;
+  }
+
+  if (POOL_create(POOL_MAX_THREADS + 1, 1)) {
+    printf("FAIL: should not create POOL exceeding POOL_MAX_THREADS\n");
+    return 1;
+  }
+
+  POOL_joinJobs(NULL);
+
+  {
+    POOL_ctx* const testCtx = POOL_create(1, 1);
+    if (!testCtx) {
+      printf("FAIL: could not create POOL for resize test\n");
+      return 1;
+    }
+    if (POOL_resize(testCtx, (size_t)-1) == 0) {
+      printf("FAIL: POOL_resize with overflowing numThreads should fail\n");
+      POOL_free(testCtx);
+      return 1;
+    }
+    if (POOL_resize(testCtx, POOL_MAX_THREADS + 1) == 0) {
+      printf("FAIL: POOL_resize exceeding POOL_MAX_THREADS should fail\n");
+      POOL_free(testCtx);
+      return 1;
+    }
+    POOL_free(testCtx);
+  }
+
   for (numThreads = 1; numThreads <= 4; ++numThreads) {
     size_t queueSize;
     for (queueSize = 0; queueSize <= 2; ++queueSize) {