# CVE-2021-47196: linux: In the Linux kernel, the following vulnerability has been resolved:  RDMA/core: Set send and receive CQ before forwar...

CVE-2021-47196 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47196, released April 10, 2024. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2021-47196
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0022
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Apr 10, 2024

## Description

In the Linux kernel, the following vulnerability has been resolved:  RDMA/core: Set send and receive CQ before forwarding to the driver  Preset both receive and send CQ pointers prior to call to the drivers and overwrite it later again till the mlx4 is going to be changed do not overwrite ibqp properties.  This change is needed for mlx5, because in case of QP creation failure, it will go to the path of QP destroy which relies on proper CQ pointers.   BUG: KASAN: use-after-free in create_qp.cold+0x164/0x16e [mlx5_ib]  Write of size 8 at addr ffff8880064c55c0 by task a.out/246   CPU: 0 PID: 246 Comm: a.out Not tainted 5.15.0+ #291  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014  Call Trace:   dump_stack_lvl+0x45/0x59   print_address_description.constprop.0+0x1f/0x140   kasan_report.cold+0x83/0xdf   create_qp.cold+0x164/0x16e [mlx5_ib]   mlx5_ib_create_qp+0x358/0x28a0 [mlx5_ib]   create_qp.part.0+0x45b/0x6a0 [ib_core]   ib_create_qp_user+0x97/0x150 [ib_core]   ib_uverbs_handler_UVERBS_METHOD_QP_CREATE+0x92c/0x1250 [ib_uverbs]   ib_uverbs_cmd_verbs+0x1c38/0x3150 [ib_uverbs]   ib_uverbs_ioctl+0x169/0x260 [ib_uverbs]   __x64_sys_ioctl+0x866/0x14d0   do_syscall_64+0x3d/0x90   entry_SYSCALL_64_after_hwframe+0x44/0xae   Allocated by task 246:   kasan_save_stack+0x1b/0x40   __kasan_kmalloc+0xa4/0xd0   create_qp.part.0+0x92/0x6a0 [ib_core]   ib_create_qp_user+0x97/0x150 [ib_core]   ib_uverbs_handler_UVERBS_METHOD_QP_CREATE+0x92c/0x1250 [ib_uverbs]   ib_uverbs_cmd_verbs+0x1c38/0x3150 [ib_uverbs]   ib_uverbs_ioctl+0x169/0x260 [ib_uverbs]   __x64_sys_ioctl+0x866/0x14d0   do_syscall_64+0x3d/0x90   entry_SYSCALL_64_after_hwframe+0x44/0xae   Freed by task 246:   kasan_save_stack+0x1b/0x40   kasan_set_track+0x1c/0x30   kasan_set_free_info+0x20/0x30   __kasan_slab_free+0x10c/0x150   slab_free_freelist_hook+0xb4/0x1b0   kfree+0xe7/0x2a0   create_qp.part.0+0x52b/0x6a0 [ib_core]   ib_create_qp_user+0x97/0x150 [ib_core]   ib_uverbs_handler_UVERBS_METHOD_QP_CREATE+0x92c/0x1250 [ib_uverbs]   ib_uverbs_cmd_verbs+0x1c38/0x3150 [ib_uverbs]   ib_uverbs_ioctl+0x169/0x260 [ib_uverbs]   __x64_sys_ioctl+0x866/0x14d0   do_syscall_64+0x3d/0x90   entry_SYSCALL_64_after_hwframe+0x44/0xae

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.15.5-1 | [DEBIAN-CVE-2021-47196](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47196.md) | Apr 10, 2024 |
| Linux | linux Debian 13.5 (trixie) | 5.15.5-1 | [DEBIAN-CVE-2021-47196](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47196.md) | Apr 10, 2024 |
| Linux | linux Debian 14 | 5.15.5-1 | [DEBIAN-CVE-2021-47196](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47196.md) | Apr 10, 2024 |

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