diff --git a/ext/session/php_session.h b/ext/session/php_session.h
index 08c08b9a024a..752199198953 100644
--- a/ext/session/php_session.h
+++ b/ext/session/php_session.h
@@ -148,6 +148,7 @@ typedef struct _php_ps_globals {
 	int module_number;
 	php_random_status_state_pcgoneseq128xslrr64 random_state;
 	php_random_algo_with_state random;
+	bool gc_random_seeded; /* false until first GC check; reseeds after fork */
 	zend_long gc_probability;
 	zend_long gc_divisor;
 	zend_long gc_maxlifetime;
diff --git a/ext/session/session.c b/ext/session/session.c
index 1fdfc5d1073f..9c2735cb03c1 100644
--- a/ext/session/session.c
+++ b/ext/session/session.c
@@ -392,8 +392,22 @@ static zend_long php_session_gc(bool immediate)
 
 	/* GC must be done before reading session data. */
 	if ((PS(mod_data) || PS(mod_user_implemented))) {
-		/* Use probability-based GC if not forced and probability is configured */
 		if (!collect && PS(gc_probability) > 0) {
+			/* Reseed PS(random) on first use per process. GINIT runs in the
+			 * master process before SAPIs like PHP-FPM fork their workers, so
+			 * all workers would otherwise inherit and replay the same PCG
+			 * sequence. One CSPRNG call here breaks the correlation. */
+			if (UNEXPECTED(!PS(gc_random_seeded))) {
+				php_random_uint128_t seed;
+				if (php_random_bytes_silent(&seed, sizeof(seed)) == FAILURE) {
+					seed = php_random_uint128_constant(
+						php_random_generate_fallback_seed(),
+						php_random_generate_fallback_seed()
+					);
+				}
+				php_random_pcgoneseq128xslrr64_seed128(PS(random).state, seed);
+				PS(gc_random_seeded) = true;
+			}
 			collect = php_random_range(PS(random), 0, PS(gc_divisor) - 1) < PS(gc_probability);
 		}
 
@@ -2891,14 +2905,7 @@ static PHP_GINIT_FUNCTION(ps)
 		.algo = &php_random_algo_pcgoneseq128xslrr64,
 		.state = &ps_globals->random_state,
 	};
-	php_random_uint128_t seed;
-	if (php_random_bytes_silent(&seed, sizeof(seed)) == FAILURE) {
-		seed = php_random_uint128_constant(
-			php_random_generate_fallback_seed(),
-			php_random_generate_fallback_seed()
-		);
-	}
-	php_random_pcgoneseq128xslrr64_seed128(ps_globals->random.state, seed);
+	ps_globals->gc_random_seeded = false;
 }
 
 static PHP_MINIT_FUNCTION(session)