CVE-2025-21673: Double Free
First published: Fri Jan 31 2025(Updated: )
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>
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Kernel | ||
| Linux Kernel | >=5.14.19<5.15 | |
| Linux Kernel | >=5.15.3<6.6.74 | |
| Linux Kernel | >=6.7<6.12.11 | |
| Linux Kernel | =6.13-rc1 | |
| Linux Kernel | =6.13-rc2 | |
| Linux Kernel | =6.13-rc3 | |
| Linux Kernel | =6.13-rc4 | |
| Linux Kernel | =6.13-rc5 | |
| Linux Kernel | =6.13-rc6 | |
| Linux Kernel | =6.13-rc7 |
Never miss a vulnerability like this again
Sign up to SecAlerts for real-time vulnerability data matched to your software, aggregated from hundreds of sources.
Reference Links
Frequently Asked Questions
What is the severity of CVE-2025-21673?
CVE-2025-21673 is rated as a medium severity vulnerability.
How do I fix CVE-2025-21673?
Fixing CVE-2025-21673 involves updating to the latest version of the Linux kernel where this vulnerability has been patched.
What types of systems are affected by CVE-2025-21673?
CVE-2025-21673 affects systems running the Linux kernel, specifically those utilizing SMB client functionality.
What is the potential impact of CVE-2025-21673?
The potential impact of CVE-2025-21673 includes the risk of a double free vulnerability leading to arbitrary code execution or denial of service.
When was CVE-2025-21673 disclosed?
CVE-2025-21673 was disclosed as part of a series of kernel vulnerabilities addressing SMB client issues.
- agent/type
- agent/description
- agent/first-publish-date
- agent/source
- agent/references
- agent/author
- agent/guess-ai
- agent/software-canonical-lookup
- collector/nvd-api
- source/NVD
- agent/remedy
- agent/weakness
- agent/severity
- agent/last-modified-date
- agent/softwarecombine
- agent/tags
- agent/event
- vendor/linux
- canonical/linux kernel
- version/linux kernel/5.14.19
- version/linux kernel/5.15.3
- version/linux kernel/6.7
- version/linux kernel/6.13-rc1
- version/linux kernel/6.13-rc2
- version/linux kernel/6.13-rc3
- version/linux kernel/6.13-rc4
- version/linux kernel/6.13-rc5
- version/linux kernel/6.13-rc6
- version/linux kernel/6.13-rc7