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Vulnerability · Published Jan 31, 2025 · Assigned by Linux

CVE-2025-21673smb: client: fix double free of TCP_Server_Info::hostname

Critical 9.8

In plain English

A critical-severity double free in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.8Critical
Exploit odds (30 days)0.4%top 63.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix double free of TCP_Server_Info::hostname When shutting down the server in cifs_put_tcp_session(), cifsd thread might be reconnecting to multiple DFS targets before it realizes it should exit the loop, so @server->hostname can't be freed as long as cifsd thread isn't done. Otherwise the following can happen: RIP: 0010:__slab_free+0x223/0x3c0 Code: 5e 41 5f c3 cc cc cc cc 4c 89 de 4c 89 cf 44 89 44 24 08 4c 89 1c 24 e8 fb cf 8e 00 44 8b 44 24 08 4c 8b 1c 24 e9 5f fe ff ff <0f> 0b 41 f7 45 08 00 0d 21 00 0f 85 2d ff ff ff e9 1f ff ff ff 80 RSP: 0018:ffffb26180dbfd08 EFLAGS: 00010246 RAX: ffff8ea34728e510 RBX: ffff8ea34728e500 RCX: 0000000000800068 RDX: 0000000000800068 RSI: 0000000000000000 RDI: ffff8ea340042400 RBP: ffffe112041ca380 R08: 0000000000000001 R09: 0000000000000000 R10: 6170732e31303000 R11: 70726f632e786563 R12: ffff8ea34728e500 R13: ffff8ea340042400 R14: ffff8ea34728e500 R15: 0000000000800068 FS: 0000000000000000(0000) GS:ffff8ea66fd80000(0000) 000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffc25376080 CR3: 000000012a2ba001 CR4: PKRU: 55555554 Call Trace: <TASK> ? show_trace_log_lvl+0x1c4/0x2df ? show_trace_log_lvl+0x1c4/0x2df ? __reconnect_target_unlocked+0x3e/0x160 [cifs] ? __die_body.cold+0x8/0xd ? die+0x2b/0x50 ? do_trap+0xce/0x120 ? __slab_free+0x223/0x3c0 ? do_error_trap+0x65/0x80 ? __slab_free+0x223/0x3c0 ? exc_invalid_op+0x4e/0x70 ? __slab_free+0x223/0x3c0 ? asm_exc_invalid_op+0x16/0x20 ? __slab_free+0x223/0x3c0 ? extract_hostname+0x5c/0xa0 [cifs] ? extract_hostname+0x5c/0xa0 [cifs] ? __kmalloc+0x4b/0x140 __reconnect_target_unlocked+0x3e/0x160 [cifs] reconnect_dfs_server+0x145/0x430 [cifs] cifs_handle_standard+0x1ad/0x1d0 [cifs] cifs_demultiplex_thread+0x592/0x730 [cifs] ? __pfx_cifs_demultiplex_thread+0x10/0x10 [cifs] kthread+0xdd/0x100 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x29/0x50 </TASK>

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linuxno fix listedDEBIAN-CVE-2025-21673
Debian:13linux6.12.11-1DEBIAN-CVE-2025-21673
Debian:14linux6.12.11-1DEBIAN-CVE-2025-21673
Ubuntu:22.04:LTSlinuxno fix listedUBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux6.8.0-62.65USN-7595-1
Ubuntu:24.04:LTSlinux6.8.0-62.65UBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-awsno fix listedUBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-aws6.8.0-1030.32USN-7595-1
Ubuntu:24.04:LTSlinux-aws6.8.0-1030.32UBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1030.32~22.04.1UBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1030.32~22.04.1USN-7595-1
Ubuntu:22.04:LTSlinux-azureno fix listedUBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-azure6.8.0-1030.35UBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-azure6.8.0-1030.35USN-7596-1
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-azure-6.116.11.0-1013.13~24.04.1USN-7448-1
Ubuntu:24.04:LTSlinux-azure-6.116.11.0-1013.13~24.04.1UBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1030.35~22.04.1USN-7596-1
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1030.35~22.04.1UBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-azure-fdeno fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-azure-nvidia6.8.0-1018.19USN-7596-2
Ubuntu:24.04:LTSlinux-azure-nvidia6.8.0-1018.19UBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-gcpno fix listedUBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-gcp6.8.0-1031.33UBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-gcp6.8.0-1031.33USN-7595-5
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-gcp-6.116.11.0-1013.13~24.04.1UBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1031.33~22.04.1USN-7595-5
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1031.33~22.04.1UBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-gkeno fix listedUBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-gke6.8.0-1026.30UBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-gke6.8.0-1026.30USN-7595-1
Ubuntu:22.04:LTSlinux-gkeopno fix listedUBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1013.15UBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1013.15USN-7595-1
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-hwe-6.116.11.0-24.24~24.04.1UBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-hwe-6.116.11.0-24.24~24.04.1USN-7445-1
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-hwe-6.86.8.0-64.67~22.04.1UBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-ibmno fix listedUBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-ibm6.8.0-1027.27USN-7595-1
Ubuntu:24.04:LTSlinux-ibm6.8.0-1027.27UBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1027.27~22.04.1UBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-intel-iotgno fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-kvmno fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-lowlatencyno fix listedUBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-62.65.1USN-7595-1
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-62.65.1UBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.116.11.0-1012.13~24.04.1USN-7445-1
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.116.11.0-1012.13~24.04.1UBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-62.65.1~22.04.1USN-7595-1
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-62.65.1~22.04.1UBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-nvidiano fix listedUBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1029.32UBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1029.32USN-7595-1
Ubuntu:24.04:LTSlinux-nvidia-6.116.11.0-1007.7UBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1029.32~22.04.1USN-7595-1
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1029.32~22.04.1UBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1029.32.1USN-7595-1
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1029.32.1UBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-nvidia-tegrano fix listedUBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1008.8UBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-nvidia-tegra-igxno fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-oem-6.116.11.0-1020.20USN-7445-1
Ubuntu:24.04:LTSlinux-oem-6.116.11.0-1020.20UBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-oem-6.86.8.0-1029.29UBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-oem-6.86.8.0-1029.29USN-7595-1
Ubuntu:22.04:LTSlinux-oracleno fix listedUBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-oracle6.8.0-1027.28UBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-oracle6.8.0-1027.28USN-7595-4
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1027.28~22.04.1UBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1027.28~22.04.1USN-7595-4
Ubuntu:22.04:LTSlinux-raspino fix listedUBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-raspi6.8.0-1029.33UBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-raspi6.8.0-1029.33USN-7595-4
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-riscv-6.86.8.0-62.65~22.04.1UBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2025-21673
Ubuntu:24.04:LTSlinux-xilinx6.8.0-1017.18UBUNTU-CVE-2025-21673
Ubuntu:22.04:LTSlinux-xilinx-zynqmpno fix listedUBUNTU-CVE-2025-21673

Affected products (as reported)

VendorProductVersions
Linux Linux 7be3248f313930ff3d3436d4e9ddbe9fccc1f541 – before 35455f6c9326a8d10e91f3d5ba9260ab795b7d9a7be3248f313930ff3d3436d4e9ddbe9fccc1f541 – before 1ea68070338518a1d31ce71e6abfe1b30001b27a7be3248f313930ff3d3436d4e9ddbe9fccc1f541 – before a2be5f2ba34d0c6d5ef2624b24e3d852561fcd6a7be3248f313930ff3d3436d4e9ddbe9fccc1f541 – before fa2f9906a7b333ba757a7dbae0713d8a5396186e49f933bb3016269dc50074eac5f6033d127644f11c35a216ef77db708178ca225d796271f2f60a7a5.14.19 – before 5.155.15.3 – before 5.16
Linux Linux 5.16

Weakness: CWE-415 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References