DEBIAN-CVE-2026-64437

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Source
https://security-tracker.debian.org/tracker/CVE-2026-64437
Import Source
https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-64437.json
JSON Data
https://api.osv.dev/v1/vulns/DEBIAN-CVE-2026-64437
Upstream
Published
2026-07-25T10:17:28Z
Modified
2026-09-14T17:03:27Z
Severity
  • 8.8 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H CVSS Calculator
Summary
[none]
Details

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free of a deferred file_lock on SMB2_CLOSE then SMB2_CANCEL Commit f580d27e8928 ("ksmbd: fix use-after-free of a deferred file_lock on double SMB2_CANCEL") made smb2_cancel() skip a work whose state is KSMBD_WORK_CANCELLED, so its cancel_fn cannot be fired a second time. But KSMBD_WORK has three states (ACTIVE, CANCELLED, CLOSED), and the same freeing producer path is reached for CLOSED too: SMB2_CLOSE on the locking handle -> set_close_state_blocked_works() sets the deferred work's state to KSMBD_WORK_CLOSED and wakes the smb2_lock() worker. The worker takes the non-ACTIVE early-exit, locks_free_lock()s the file_lock and, because the state is not KSMBD_WORK_CANCELLED, takes the STATUS_RANGE_NOT_LOCKED branch with "goto out2" -- which, like the cancelled branch, skips release_async_work(). The work stays on conn->async_requests with a live cancel_fn = smb2_remove_blocked_lock pointing at the freed file_lock. A subsequent SMB2_CANCEL for the same AsyncId then passes the KSMBD_WORK_CANCELLED-only guard (its state is KSMBD_WORK_CLOSED), so smb2_cancel() fires cancel_fn again over the freed file_lock -- the same use-after-free fixed, via SMB2_CLOSE instead of a first SMB2_CANCEL: BUG: KASAN: slab-use-after-free in __locks_delete_block __locks_delete_block locks_delete_block ksmbd_vfs_posix_lock_unblock smb2_remove_blocked_lock smb2_cancel <- 2nd SMB2_CANCEL fires cancel_fn handle_ksmbd_work Allocated by ...: locks_alloc_lock <- smb2_lock Freed by ...: locks_free_lock <- smb2_lock (non-ACTIVE early-exit) ... cache file_lock_cache of size 192 Reproduced on mainline 7.1-rc7 (which already contains f580d27e8928) with KASAN by an authenticated SMB client; the double-SMB2_CANCEL control is silent on that kernel, so the splat is attributable to the CLOSE trigger. Only an ACTIVE deferred work may have its cancel_fn fired: both terminal states (CANCELLED and CLOSED) reach the smb2_lock() early-exit that frees the file_lock and skips release_async_work(). Guard on KSMBD_WORK_ACTIVE so any non-active work is skipped.

References

Affected packages

Debian:12 / linux

Package

Name
linux
Purl
pkg:deb/debian/linux?arch=source&distro=bookworm

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
6.1.180-1

Affected versions

6.*
6.1.27-1
6.1.37-1
6.1.38-1
6.1.38-2~bpo11+1
6.1.38-2
6.1.38-3
6.1.38-4~bpo11+1
6.1.38-4
6.1.52-1
6.1.55-1~bpo11+1
6.1.55-1
6.1.64-1
6.1.66-1
6.1.67-1
6.1.69-1~bpo11+1
6.1.69-1
6.1.76-1~bpo11+1
6.1.76-1
6.1.82-1
6.1.85-1
6.1.90-1~bpo11+1
6.1.90-1
6.1.94-1~bpo11+1
6.1.94-1
6.1.98-1
6.1.99-1
6.1.106-1
6.1.106-2
6.1.106-3
6.1.112-1
6.1.115-1
6.1.119-1
6.1.123-1
6.1.124-1
6.1.128-1
6.1.129-1
6.1.133-1
6.1.135-1
6.1.137-1
6.1.139-1
6.1.140-1
6.1.147-1
6.1.148-1
6.1.153-1
6.1.158-1
6.1.159-1
6.1.162-1
6.1.164-1
6.1.170-1
6.1.170-2
6.1.170-3
6.1.172-1
6.1.174-1
6.1.176-1
6.1.177-1

Ecosystem specific 

{
    "urgency":  "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-64437.json"

Debian:13 / linux

Package

Name
linux
Purl
pkg:deb/debian/linux?arch=source&distro=trixie

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
6.12.96-1

Affected versions

6.*
6.12.38-1
6.12.41-1
6.12.43-1~bpo12+1
6.12.43-1
6.12.48-1
6.12.57-1~bpo12+1
6.12.57-1
6.12.63-1~bpo12+1
6.12.63-1
6.12.69-1~bpo12+1
6.12.69-1
6.12.73-1~bpo12+1
6.12.73-1
6.12.74-1
6.12.74-2~bpo12+1
6.12.74-2
6.12.85-1~bpo12+1
6.12.85-1
6.12.86-1~bpo12+1
6.12.86-1
6.12.88-1~bpo12+1
6.12.88-1
6.12.90-1~bpo12+1
6.12.90-1
6.12.90-2~bpo12+1
6.12.90-2
6.12.94-1~bpo12+1
6.12.94-1
6.12.95-1~bpo12+1
6.12.95-1

Ecosystem specific 

{
    "urgency":  "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-64437.json"

Debian:14 / linux

Package

Name
linux
Purl
pkg:deb/debian/linux?arch=source&distro=forky

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
7.1.4-1

Affected versions

6.*
6.12.38-1
6.12.41-1
6.12.43-1~bpo12+1
6.12.43-1
6.12.48-1
6.12.57-1~bpo12+1
6.12.57-1
6.12.63-1~bpo12+1
6.12.63-1
6.12.69-1~bpo12+1
6.12.69-1
6.12.73-1~bpo12+1
6.12.73-1
6.12.74-1
6.12.74-2~bpo12+1
6.12.74-2
6.12.85-1~bpo12+1
6.12.85-1
6.12.86-1~bpo12+1
6.12.86-1
6.12.88-1~bpo12+1
6.12.88-1
6.12.90-1~bpo12+1
6.12.90-1
6.12.90-2~bpo12+1
6.12.90-2
6.12.94-1~bpo12+1
6.12.94-1
6.12.95-1~bpo12+1
6.12.95-1
6.12.96-1
6.12.100-1
6.12.101-1
6.12.105-1
6.12.107-1
6.13~rc6-1~exp1
6.13~rc7-1~exp1
6.13.2-1~exp1
6.13.3-1~exp1
6.13.4-1~exp1
6.13.5-1~exp1
6.13.6-1~exp1
6.13.7-1~exp1
6.13.8-1~exp1
6.13.9-1~exp1
6.13.10-1~exp1
6.13.11-1~exp1
6.14.3-1~exp1
6.14.5-1~exp1
6.14.6-1~exp1
6.15~rc7-1~exp1
6.15-1~exp1
6.15.1-1~exp1
6.15.2-1~exp1
6.15.3-1~exp1
6.15.4-1~exp1
6.15.5-1~exp1
6.15.6-1~exp1
6.16~rc7-1~exp1
6.16-1~exp1
6.16.1-1~exp1
6.16.3-1~bpo13+1
6.16.3-1
6.16.5-1
6.16.6-1
6.16.7-1
6.16.8-1
6.16.9-1
6.16.10-1
6.16.11-1
6.16.12-1~bpo13+1
6.16.12-1
6.16.12-2
6.17.2-1~exp1
6.17.5-1~exp1
6.17.6-1
6.17.7-1
6.17.7-2
6.17.8-1~bpo13+1
6.17.8-1
6.17.9-1
6.17.10-1
6.17.11-1
6.17.12-1
6.17.13-1~bpo13+1
6.17.13-1
6.18~rc4-1~exp1
6.18~rc4-1~exp2
6.18~rc5-1~exp1
6.18~rc6-1~exp1
6.18~rc7-1~exp1
6.18.1-1~exp1
6.18.2-1~exp1
6.18.3-1
6.18.5-1~bpo13+1
6.18.5-1
6.18.8-1
6.18.9-1~bpo13+1
6.18.9-1
6.18.10-1
6.18.12-1~bpo13+1
6.18.12-1
6.18.13-1
6.18.14-1
6.18.15-1~bpo13+1
6.18.15-1
6.19~rc4-1~exp1
6.19~rc5-1~exp1
6.19~rc6-1~exp1
6.19~rc7-1~exp1
6.19~rc8-1~exp1
6.19-1~exp1
6.19.2-1~exp1
6.19.3-1~exp1
6.19.4-1~exp1
6.19.5-1~exp1
6.19.6-1
6.19.6-2~bpo13+1
6.19.6-2
6.19.8-1~bpo13+1
6.19.8-1
6.19.10-1~bpo13+1
6.19.10-1
6.19.11-1~bpo13+1
6.19.11-1
6.19.12-1
6.19.13-1~bpo13+1
6.19.13-1
6.19.14-1~bpo13+1
6.19.14-1
7.*
7.0-1~exp1
7.0.1-1~exp1
7.0.3-1
7.0.4-1~bpo13+1
7.0.4-1
7.0.7-1~bpo13+1
7.0.7-1
7.0.9-1~bpo13+1
7.0.9-1
7.0.10-1~bpo13+1
7.0.10-1
7.0.12-1
7.0.12-2~bpo13+1
7.0.12-2
7.0.13-1~bpo13+1
7.0.13-1
7.0.14-1
7.1~rc2-1~exp1
7.1~rc3-1~exp1
7.1~rc4-1~exp1
7.1~rc4-1~exp2
7.1~rc5-1~exp1
7.1~rc7-1~exp1
7.1.1-1~exp1
7.1.2-1~exp1
7.1.3-1~bpo13+1
7.1.3-1
7.1.3-1+sunvdc

Ecosystem specific 

{
    "urgency":  "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-64437.json"

Debian:12 / linux-6.12

Package

Name
linux-6.12
Purl
pkg:deb/debian/linux-6.12?arch=source&distro=bookworm

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
6.12.100-1~deb12u1

Ecosystem specific 

{
    "urgency":  "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-64437.json"