Double Free

In the Linux kernel, the following vulnerability has been resolved: ext4: fix dirtyclusters double decrement on fs shutdown fstests test generic/388 occasionally reproduces a warning in ext4_put_super() associated with the dirty clusters count: WARNING: CPU: 7 PID: 76064 at fs/ext4/super.c:1324 ext4_put_super+0x48c/0x590 [ext4] Tracing the failure shows that the warning fires due to an s_dirtyclusters_counter value of -1. IOW, this appears to be a spurious decrement as opposed to some sort of leak. Further tracing of the dirty cluster count deltas and an LLM scan of the resulting output identified the cause as a double decrement in the error path between ext4_mb_mark_diskspace_used() and the caller ext4_mb_new_blocks(). First, note that generic/388 is a shutdown vs. fsstress test and so produces a random set of operations and shutdown injections. In the problematic case, the shutdown triggers an error return from the ext4_handle_dirty_metadata() call(s) made from ext4_mb_mark_context(). The changed value is non-zero at this point, so ext4_mb_mark_diskspace_used() does not exit after the error bubbles up from ext4_mb_mark_context(). Instead, the former decrements both cluster counters and returns the error up to ext4_mb_new_blocks(). The latter falls into the !ar->len out path which decrements the dirty clusters counter a second time, creating the inconsistency. To avoid this problem and simplify ownership of the cluster reservation in this codepath, lift the counter reduction to a single place in the caller. This makes it more clear that ext4_mb_new_blocks() is responsible for acquiring cluster reservation (via ext4_claim_free_clusters()) in the !delalloc case as well as releasing it, regardless of whether it ends up consumed or returned due to failure.Show less

In the Linux kernel, the following vulnerability has been resolved: net: hns3: fix double free issue for tx spare buffer In hns3_set_ringparam(), a temporary copy (tmp_rings) of the ring structure is created for rollback. However, the tx_spare pointer in the original ring handle is incorrectly left pointing to the old backup memory. Later, if memory allocation fails in hns3_init_all_ring() during the setup, the error path attempts to free all newly allocated rings. Since tx_spare contains a stale (non-NULL) pointer from the backup, it is mistaken for a newly allocated buffer and is erroneously freed, leading to a double-free of the backup memory. The root cause is that the tx_spare field was not cleared after its value was saved in tmp_rings, leaving a dangling pointer. Fix this by setting tx_spare to NULL in the original ring structure when the creation of the new `tx_spare` fails. This ensures the error cleanup path only frees genuinely newly allocated buffers.Show less

In the Linux kernel, the following vulnerability has been resolved: RDMA/rxe: Fix double free in rxe_srq_from_init In rxe_srq_from_init(), the queue pointer 'q' is assigned to 'srq->rq.queue' before copying the SRQ number to user space. If copy_to_user() fails, the function calls rxe_queue_cleanup() to free the queue, but leaves the now-invalid pointer in 'srq->rq.queue'. The caller of rxe_srq_from_init() (rxe_create_srq) eventually calls rxe_srq_cleanup() upon receiving the error, which triggers a second rxe_queue_cleanup() on the same memory, leading to a double free. The call trace looks like this: kmem_cache_free+0x.../0x... rxe_queue_cleanup+0x1a/0x30 [rdma_rxe] rxe_srq_cleanup+0x42/0x60 [rdma_rxe] rxe_elem_release+0x31/0x70 [rdma_rxe] rxe_create_srq+0x12b/0x1a0 [rdma_rxe] ib_create_srq_user+0x9a/0x150 [ib_core] Fix this by moving 'srq->rq.queue = q' after copy_to_user.Show less

In the Linux kernel, the following vulnerability has been resolved: net/rds: reset op_nents when zerocopy page pin fails When iov_iter_get_pages2() fails in rds_message_zcopy_from_user(), the pinned pages are released with put_page(), and rm->data.op_mmp_znotifier is cleared. But we fail to properly clear rm->data.op_nents. Later when rds_message_purge() is called from rds_sendmsg() the cleanup loop iterates over the incorrectly non zero number of op_nents and frees them again. Fix this by properly resetting op_nents when it should be in rds_message_zcopy_from_user().Show less

NetBSD prior to commit ec8451e contains a race condition vulnerability in cryptodev_op() within the opencrypto subsystem that allows local attackers to trigger a double-free condition by concurrently issuing CIOCCRYPT operations on the same session identifier on SMP systems. Attackers can exploit mutable per-operation state embedded in the csession struct to corrupt kernel heap memory.Show less

libbabl 0.1.62 contains a broken double free detection vulnerability that allows attackers to bypass memory safety checks by exploiting signature overwriting in freed chunks. Attackers can call babl_free() twice on the same pointer without triggering detection, as libc's malloc metadata overwrites babl's signature field upon freeing, enabling potential memory corruption and code execution.Show less

PoDoFo is a C++17 PDF manipulation library. From 1.0.0 to before 1.0.4, a double-free vulnerability exists in compute_hash_to_sign() in src/podofo/private/OpenSSLInternal_Ripped.cpp. If EVP_DigestFinal fails after buf has already been freed, the Error label frees buf a second time, causing heap corruption. This vulnerability is fixed in 1.0.4.Show less

In the Linux kernel, the following vulnerability has been resolved: spi: rockchip-sfc: Fix double-free in remove() callback The driver uses devm_spi_register_controller() for registration, which automatically unregisters the controller via devm cleanup when the device is removed. The manual call to spi_unregister_controller() in the remove() callback can lead to a double-free. And to make sure controller is unregistered before DMA buffer is unmapped, switch to use spi_register_controller() in probe().Show less

In the Linux kernel, the following vulnerability has been resolved: scsi: qla2xxx: Completely fix fcport double free In qla24xx_els_dcmd_iocb() sp->free is set to qla2x00_els_dcmd_sp_free(). When an error happens, this function is called by qla2x00_sp_release(), when kref_put() releases the first and the last reference. qla2x00_els_dcmd_sp_free() frees fcport by calling qla2x00_free_fcport(). Doing it one more time after kref_put() is a bad idea.Show less

In the Linux kernel, the following vulnerability has been resolved: cpufreq: governor: fix double free in cpufreq_dbs_governor_init() error path When kobject_init_and_add() fails, cpufreq_dbs_governor_init() calls kobject_put(&dbs_data->attr_set.kobj). The kobject release callback cpufreq_dbs_data_release() calls gov->exit(dbs_data) and kfree(dbs_data), but the current error path then calls gov->exit(dbs_data) and kfree(dbs_data) again, causing a double free. Keep the direct kfree(dbs_data) for the gov->init() failure path, but after kobject_init_and_add() has been called, let kobject_put() handle the cleanup through cpufreq_dbs_data_release().Show less

In the Linux kernel, the following vulnerability has been resolved: dm: clear cloned request bio pointer when last clone bio completes Stale rq->bio values have been observed to cause double-initialization of cloned bios in request-based device-mapper targets, leading to use-after-free and double-free scenarios. One such case occurs when using dm-multipath on top of a PCIe NVMe namespace, where cloned request bios are freed during blk_complete_request(), but rq->bio is left intact. Subsequent clone teardown then attempts to free the same bios again via blk_rq_unprep_clone(). The resulting double-free path looks like: nvme_pci_complete_batch() nvme_complete_batch() blk_mq_end_request_batch() blk_complete_request() // called on a DM clone request bio_endio() // first free of all clone bios ... rq->end_io() // end_clone_request() dm_complete_request(tio->orig) dm_softirq_done() dm_done() dm_end_request() blk_rq_unprep_clone() // second free of clone bios Fix this by clearing the clone request's bio pointer when the last cloned bio completes, ensuring that later teardown paths do not attempt to free already-released bios.Show less

In the Linux kernel, the following vulnerability has been resolved: net: mana: Fix double destroy_workqueue on service rescan PCI path While testing corner cases in the driver, a use-after-free crash was found on the service rescan PCI path. When mana_serv_reset() calls mana_gd_suspend(), mana_gd_cleanup() destroys gc->service_wq. If the subsequent mana_gd_resume() fails with -ETIMEDOUT or -EPROTO, the code falls through to mana_serv_rescan() which triggers pci_stop_and_remove_bus_device(). This invokes the PCI .remove callback (mana_gd_remove), which calls mana_gd_cleanup() a second time, attempting to destroy the already- freed workqueue. Fix this by NULL-checking gc->service_wq in mana_gd_cleanup() and setting it to NULL after destruction. Call stack of issue for reference: [Sat Feb 21 18:53:48 2026] Call Trace: [Sat Feb 21 18:53:48 2026] <TASK> [Sat Feb 21 18:53:48 2026] mana_gd_cleanup+0x33/0x70 [mana] [Sat Feb 21 18:53:48 2026] mana_gd_remove+0x3a/0xc0 [mana] [Sat Feb 21 18:53:48 2026] pci_device_remove+0x41/0xb0 [Sat Feb 21 18:53:48 2026] device_remove+0x46/0x70 [Sat Feb 21 18:53:48 2026] device_release_driver_internal+0x1e3/0x250 [Sat Feb 21 18:53:48 2026] device_release_driver+0x12/0x20 [Sat Feb 21 18:53:48 2026] pci_stop_bus_device+0x6a/0x90 [Sat Feb 21 18:53:48 2026] pci_stop_and_remove_bus_device+0x13/0x30 [Sat Feb 21 18:53:48 2026] mana_do_service+0x180/0x290 [mana] [Sat Feb 21 18:53:48 2026] mana_serv_func+0x24/0x50 [mana] [Sat Feb 21 18:53:48 2026] process_one_work+0x190/0x3d0 [Sat Feb 21 18:53:48 2026] worker_thread+0x16e/0x2e0 [Sat Feb 21 18:53:48 2026] kthread+0xf7/0x130 [Sat Feb 21 18:53:48 2026] ? __pfx_worker_thread+0x10/0x10 [Sat Feb 21 18:53:48 2026] ? __pfx_kthread+0x10/0x10 [Sat Feb 21 18:53:48 2026] ret_from_fork+0x269/0x350 [Sat Feb 21 18:53:48 2026] ? __pfx_kthread+0x10/0x10 [Sat Feb 21 18:53:48 2026] ret_from_fork_asm+0x1a/0x30 [Sat Feb 21 18:53:48 2026] </TASK>Show less

In the Linux kernel, the following vulnerability has been resolved: bnxt_en: Fix RSS context delete logic We need to free the corresponding RSS context VNIC in FW everytime an RSS context is deleted in driver. Commit 667ac333dbb7 added a check to delete the VNIC in FW only when netif_running() is true to help delete RSS contexts with interface down. Having that condition will make the driver leak VNICs in FW whenever close() happens with active RSS contexts. On the subsequent open(), as part of RSS context restoration, we will end up trying to create extra VNICs for which we did not make any reservation. FW can fail this request, thereby making us lose active RSS contexts. Suppose an RSS context is deleted already and we try to process a delete request again, then the HWRM functions will check for validity of the request and they simply return if the resource is already freed. So, even for delete-when-down cases, netif_running() check is not necessary. Remove the netif_running() condition check when deleting an RSS context.Show less

In the Linux kernel, the following vulnerability has been resolved: 9p/xen: protect xen_9pfs_front_free against concurrent calls The xenwatch thread can race with other back-end change notifications and call xen_9pfs_front_free() twice, hitting the observed general protection fault due to a double-free. Guard the teardown path so only one caller can release the front-end state at a time, preventing the crash. This is a fix for the following double-free: [ 27.052347] Oops: general protection fault, probably for non-canonical address 0x6b6b6b6b6b6b6b6b: 0000 [#1] SMP DEBUG_PAGEALLOC NOPTI [ 27.052357] CPU: 0 UID: 0 PID: 32 Comm: xenwatch Not tainted 6.18.0-02087-g51ab33fc0a8b-dirty #60 PREEMPT(none) [ 27.052363] RIP: e030:xen_9pfs_front_free+0x1d/0x150 [ 27.052368] Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 41 55 41 54 55 48 89 fd 48 c7 c7 48 d0 92 85 53 e8 cb cb 05 00 48 8b 45 08 48 8b 55 00 <48> 3b 28 0f 85 f9 28 35 fe 48 3b 6a 08 0f 85 ef 28 35 fe 48 89 42 [ 27.052377] RSP: e02b:ffffc9004016fdd0 EFLAGS: 00010246 [ 27.052381] RAX: 6b6b6b6b6b6b6b6b RBX: ffff88800d66e400 RCX: 0000000000000000 [ 27.052385] RDX: 6b6b6b6b6b6b6b6b RSI: 0000000000000000 RDI: 0000000000000000 [ 27.052389] RBP: ffff88800a887040 R08: 0000000000000000 R09: 0000000000000000 [ 27.052393] R10: 0000000000000000 R11: 0000000000000000 R12: ffff888009e46b68 [ 27.052397] R13: 0000000000000200 R14: 0000000000000000 R15: ffff88800a887040 [ 27.052404] FS: 0000000000000000(0000) GS:ffff88808ca57000(0000) knlGS:0000000000000000 [ 27.052408] CS: e030 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 27.052412] CR2: 00007f9714004360 CR3: 0000000004834000 CR4: 0000000000050660 [ 27.052418] Call Trace: [ 27.052420] <TASK> [ 27.052422] xen_9pfs_front_changed+0x5d5/0x720 [ 27.052426] ? xenbus_otherend_changed+0x72/0x140 [ 27.052430] ? __pfx_xenwatch_thread+0x10/0x10 [ 27.052434] xenwatch_thread+0x94/0x1c0 [ 27.052438] ? __pfx_autoremove_wake_function+0x10/0x10 [ 27.052442] kthread+0xf8/0x240 [ 27.052445] ? __pfx_kthread+0x10/0x10 [ 27.052449] ? __pfx_kthread+0x10/0x10 [ 27.052452] ret_from_fork+0x16b/0x1a0 [ 27.052456] ? __pfx_kthread+0x10/0x10 [ 27.052459] ret_from_fork_asm+0x1a/0x30 [ 27.052463] </TASK> [ 27.052465] Modules linked in: [ 27.052471] ---[ end trace 0000000000000000 ]---Show less