# CVE-2022-48726: linux: In the Linux kernel, the following vulnerability has been resolved:  RDMA/ucma: Protect mc during concurrent multicas...

CVE-2022-48726 is fixed in linux on 1 platform, first by DEBIAN-CVE-2022-48726, released June 20, 2024. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2022-48726
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0024
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 20, 2024

## Description

In the Linux kernel, the following vulnerability has been resolved:  RDMA/ucma: Protect mc during concurrent multicast leaves  Partially revert the commit mentioned in the Fixes line to make sure that allocation and erasing multicast struct are locked.    BUG: KASAN: use-after-free in ucma_cleanup_multicast drivers/infiniband/core/ucma.c:491 [inline]   BUG: KASAN: use-after-free in ucma_destroy_private_ctx+0x914/0xb70 drivers/infiniband/core/ucma.c:579   Read of size 8 at addr ffff88801bb74b00 by task syz-executor.1/25529   CPU: 0 PID: 25529 Comm: syz-executor.1 Not tainted 5.16.0-rc7-syzkaller #0   Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011   Call Trace:    __dump_stack lib/dump_stack.c:88 [inline]    dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106    print_address_description.constprop.0.cold+0x8d/0x320 mm/kasan/report.c:247    __kasan_report mm/kasan/report.c:433 [inline]    kasan_report.cold+0x83/0xdf mm/kasan/report.c:450    ucma_cleanup_multicast drivers/infiniband/core/ucma.c:491 [inline]    ucma_destroy_private_ctx+0x914/0xb70 drivers/infiniband/core/ucma.c:579    ucma_destroy_id+0x1e6/0x280 drivers/infiniband/core/ucma.c:614    ucma_write+0x25c/0x350 drivers/infiniband/core/ucma.c:1732    vfs_write+0x28e/0xae0 fs/read_write.c:588    ksys_write+0x1ee/0x250 fs/read_write.c:643    do_syscall_x64 arch/x86/entry/common.c:50 [inline]    do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80    entry_SYSCALL_64_after_hwframe+0x44/0xae  Currently the xarray search can touch a concurrently freeing mc as the xa_for_each() is not surrounded by any lock. Rather than hold the lock for a full scan hold it only for the effected items, which is usually an empty list.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.16.10-1 | [DEBIAN-CVE-2022-48726](https://patchblox.com/security/data/fix/linux/debian-cve-2022-48726.md) | Jun 20, 2024 |
| Linux | linux Debian 13.5 (trixie) | 5.16.10-1 | [DEBIAN-CVE-2022-48726](https://patchblox.com/security/data/fix/linux/debian-cve-2022-48726.md) | Jun 20, 2024 |
| Linux | linux Debian 14 | 5.16.10-1 | [DEBIAN-CVE-2022-48726](https://patchblox.com/security/data/fix/linux/debian-cve-2022-48726.md) | Jun 20, 2024 |

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