CVE-2025-21673

CVE.org · Published

Record status: Published
Identifier year (not publication year): 2025
Source publication: Jan 31, 2025
Source updated: Aug 5, 2026
Imported by cveboard: Oct 24, 2026
Source snapshot: cve_2026-10-24_midnight_baseline · Oct 24, 2026

CNA source text (English)

smb: client: fix double free of TCP_Server_Info::hostname

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>

Scoped product and version facts

Fix information unknown; no fixed version is derived here. Missing information does not prove that no fix exists.

Exploitation unknown; this catalogue does not assess exploitation.

Linux

Vendor: Linux
Product: Linux
Platforms: Unknown
Default status: unaffected

Linux · Scoped product and version facts
Version (version)	Status (status)	Version scheme (versionType)	Exclusive end (lessThan)	Inclusive end (lessThanOrEqual)	Status changes (at → status)
7be3248f313930ff3d3436d4e9ddbe9fccc1f541	`affected`	git	1ea68070338518a1d31ce71e6abfe1b30001b27a	Unavailable	None listed
7be3248f313930ff3d3436d4e9ddbe9fccc1f541	`affected`	git	a2be5f2ba34d0c6d5ef2624b24e3d852561fcd6a	Unavailable	None listed
7be3248f313930ff3d3436d4e9ddbe9fccc1f541	`affected`	git	fa2f9906a7b333ba757a7dbae0713d8a5396186e	Unavailable	None listed
49f933bb3016269dc50074eac5f6033d127644f1	`affected`	git	Unavailable	Unavailable	None listed
1c35a216ef77db708178ca225d796271f2f60a7a	`affected`	git	Unavailable	Unavailable	None listed
5.14.19	`affected`	semver	5.15	Unavailable	None listed
5.15.3	`affected`	semver	5.16	Unavailable	None listed

Linux

Vendor: Linux
Product: Linux
Platforms: Unknown
Default status: affected

Linux · Scoped product and version facts
Version (version)	Status (status)	Version scheme (versionType)	Exclusive end (lessThan)	Inclusive end (lessThanOrEqual)	Status changes (at → status)
5.16	`affected`	Unavailable	Unavailable	Unavailable	None listed
0	`unaffected`	semver	5.16	Unavailable	None listed
6.6.74	`unaffected`	semver	Unavailable	6.6.*	None listed
6.12.11	`unaffected`	semver	Unavailable	6.12.*	None listed
6.13	`unaffected`	original_commit_for_fix	Unavailable	*	None listed