diff --git a/manifest b/manifest
index 754b652e6c..9273d099a2 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Fix\sa\sproblem\sin\sfts5\ssecure-delete\scode\sthat\scould\slead\sto\sa\sbuffer\soverrun\swhen\sdealing\swith\sa\sstrategically\scorrupted\sdatabase.\sProblem\sreported\sby\sYEONBA.
-D 2026-08-11T14:16:12.940
+C Ensure\sthat\sdatabases\sopened\swith\simmutable=1\sspecified\sare\sopened\sread-only\sat\sthe\sOS\slevel.\sReport\s[bugs:/info/2026-08-11T17:21:54Z\s|\s2026-08-11T17:21:54Z]
+D 2026-08-11T18:22:01.078
 F .fossil-settings/binary-glob 61195414528fb3ea9693577e1980230d78a1f8b0a54c78cf1b9b24d0a409ed6a x
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
@@ -730,7 +730,7 @@ F src/os_setup.h 8efc64eda6a6c2f221387eefc2e7e45fd5a3d5c8337a7a83519ba4fbd2957ae
 F src/os_unix.c 5ccac2954679efc003330a5686cd2048ec9059f90f54f43900e60877e9158aa7
 F src/os_win.c 1227a3e962b017d676d985a8aec0d64f273991931ea0a0b99773651102f62df4
 F src/os_win.h c06ccc3a090cf54202ea58981c298817f3309d4c9e4d52ad0a02927346493721
-F src/pager.c 678ee3b68638ee427cc1b071b11181d0f2a827f6cb4d6ec7c12d5fa5f6a752d0
+F src/pager.c 55fecb3d8f2c9bd751109aca1df554f3ab3f2ab1c04a7fd99478cb724d73f8b4
 F src/pager.h 6137149346e6c8a3ddc1eeb40aee46381e9bc8b0fcc6dda8a1efde993c2275b8
 F src/parse.y d5a3c5b0277a441c38b35071c05e2b61ff5fc918a63309c809f4b6706179c320
 F src/pcache.c 588cc3c5ccaaadde689ed35ce5c5c891a1f7b1f4d1f56f6cf0143b74d8ee6484
@@ -1474,7 +1474,7 @@ F test/mutex1.test 2cdc320a3320521d73b8090a04a2245c1e625e5f90672882517bf5fedcec8
 F test/mutex2.test bfeaeac2e73095b2ac32285d2756e3a65e681660
 F test/nan.test 73ea63ab43668313e2f8cc9ef9e9a966672c7934f3ce76926fbe991235d07d91
 F test/nockpt.test 3db354270fc63b6871eebd40285d4c55324fb27be629c958adbff6d7fcaa8e14
-F test/nolock.test f196cf8b8fbea4e2ca345140a2b3f3b0da45c76e
+F test/nolock.test 848ac7792e7a04cc66f115756affbe064af29e14d5ffb60fcf1f456012cad84d
 F test/normalize.test 88ba50b75feaa16735ac780f675c9e111179f81da40e5e026ecb777664e18da2
 F test/notify1.test 669b2b743618efdc18ca4b02f45423d5d2304abf
 F test/notify2.test 2ecabaa1305083856b7c39cf32816b612740c161
@@ -2218,8 +2218,8 @@ F tool/warnings-clang.sh bbf6a1e685e534c92ec2bfba5b1745f34fb6f0bc2a362850723a9ee
 F tool/warnings.sh a554d13f6e5cf3760f041b87939e3d616ec6961859c3245e8ef701d1eafc2ca2
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
 F tool/winmain.c 00c8fb88e365c9017db14c73d3c78af62194d9644feaf60e220ab0f411f3604c
-P fee71cd6f7294ffd02784d26811a9d11d80e83d4075e1233b8ec0289519bb891
-R fe5b0d1837c0e6fd3c81fb867082e58f
+P 9cd4f9e9205c5a5096388397a39349db9ff5377d19095c6b20388ff799969c31
+R 32f481950c359f5b9972a7bb17af5ec3
 U dan
-Z 49eb055c28482fbfeedf08e8b54f22bf
+Z 8cda5ef2ceaae0eb741b336f4245bfe5
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 11a758ea85..79c083316e 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-9cd4f9e9205c5a5096388397a39349db9ff5377d19095c6b20388ff799969c31
+702cdeb78c19ac971892093bf9d9c90d3c6b7193518db2437d89123fffd9c5f9
diff --git a/src/pager.c b/src/pager.c
index b52886e45e..f05d12adc8 100644
--- a/src/pager.c
+++ b/src/pager.c
@@ -4999,7 +4999,15 @@ int sqlite3PagerOpen(
   */
   if( zFilename && zFilename[0] ){
     int fout = 0;                    /* VFS flags returned by xOpen() */
+    int bImmutable = sqlite3_uri_boolean(pPager->zFilename, "immutable", 0);
+    if( bImmutable ){
+      vfsFlags |= SQLITE_OPEN_READONLY;
+      vfsFlags &= ~(SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE);
+    }
     rc = sqlite3OsOpen(pVfs, pPager->zFilename, pPager->fd, vfsFlags, &fout);
+    if( bImmutable ){
+      goto act_like_temp_file;
+    }
     assert( !memDb );
     pPager->memVfs = memJM = (fout&SQLITE_OPEN_MEMORY)!=0;
     readOnly = (fout&SQLITE_OPEN_READONLY)!=0;
@@ -5039,10 +5047,9 @@ int sqlite3PagerOpen(
 #endif
       }
       pPager->noLock = sqlite3_uri_boolean(pPager->zFilename, "nolock", 0);
-      if( (iDc & SQLITE_IOCAP_IMMUTABLE)!=0
-       || sqlite3_uri_boolean(pPager->zFilename, "immutable", 0) ){
-          vfsFlags |= SQLITE_OPEN_READONLY;
-          goto act_like_temp_file;
+      if( (iDc & SQLITE_IOCAP_IMMUTABLE)!=0 ){
+        vfsFlags |= SQLITE_OPEN_READONLY;
+        goto act_like_temp_file;
       }
     }
   }else{
@@ -5062,6 +5069,7 @@ act_like_temp_file:
     pPager->eLock = EXCLUSIVE_LOCK;    /* Pretend we are in EXCLUSIVE mode */
     pPager->noLock = 1;                /* Do no locking */
     readOnly = (vfsFlags&SQLITE_OPEN_READONLY);
+    assert( readOnly==0 || readOnly==1 );
   }
 
   /* The following call to PagerSetPagesize() serves to set the value of
diff --git a/test/nolock.test b/test/nolock.test
index e732dcf13b..5dce2780fb 100644
--- a/test/nolock.test
+++ b/test/nolock.test
@@ -16,6 +16,7 @@
 
 set testdir [file dirname $argv0]
 source $testdir/tester.tcl
+set testprefix nolock
 
 unset -nocomplain tvfs_calls
 proc tvfs_reset {} {
@@ -217,4 +218,39 @@ if {[permutation]!="inmemory_journal"} {
   } {1 {unable to open database file}}
 }
 
+#-------------------------------------------------------------------------
+reset_db
+
+do_execsql_test 5.0 {
+  PRAGMA cache_size = 100;
+  CREATE TABLE t1(a INTEGER PRIMARY KEY, b UNIQUE);
+}
+
+do_execsql_test 5.1 {
+  WITH s(i) AS (
+      VALUES(1) UNION ALL SELECT i+1 FROM s WHERE i<1000
+  )
+  INSERT INTO t1 SELECT NULL, randomblob(100) FROM s;
+  BEGIN;
+    UPDATE t1 SET b=randomblob(100);
+}
+
+db_save_and_close
+db_restore
+
+# With immutable=1, the hot journal is not rolled back and the db is corrupt.
+do_test 5.2 {
+  sqlite3 db file:test.db?immutable=1 -uri 1
+  expr {[db one { PRAGMA integrity_check }]=="ok"}
+} {0}
+
+# Without immutable=1, the hot journal is correctly rolled back and the db 
+# is not corrupt.
+do_test 5.3 {
+  sqlite3 db file:test.db -uri 1
+  expr {[db one { PRAGMA integrity_check }]=="ok"}
+} {1}
+
+
+
 finish_test