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CVE-2026-72438
md/raid10: fix writes_pending and barrier reference leaks on discard failures
Published 2026-08-15 (2 months ago) by the Linux kernel CNA. Subsystem drivers/md. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-72438 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | vulnerable | 6.1.190-1 | No fix published anywhere yet, neither in Debian nor upstream for the series bookworm tracks. Watch the Debian tracker page for this CVE. Advisories for bookworm have historically landed a median of 23 days after publication. |
| Debian 13trixie | fixedDSA-6528-1 · 2026-09-29 · text | 6.12.111-1 | Update the kernel and reboot. DSA-6528-1 shipped the fix on 2026-09-29, in 6.12.111-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4817-1 · 2026-10-04 · text | 6.12.111-1~deb12u1 | Update the kernel and reboot. DLA-4817-1 shipped the fix on 2026-10-04, in 6.12.111-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
raid10_make_request() acquires a writes_pending reference with md_write_start() before calling raid10_handle_discard(). Several failure paths in raid10_handle_discard() complete the bio and return without releasing the corresponding reference, causing md_write_end() to be skipped. Call md_write_end() before returning from these failure paths to keep writes_pending accounting balanced. Additionally, discard split allocation failures can occur after wait_barrier() succeeds. Those paths return without calling allow_barrier(), leaking the associated barrier reference. Release the barrier before returning from those paths.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
drivers/md/raid10.c
- What this is
- SOFTWARE RAID (Multiple Disks) SUPPORTMAINTAINERS section matched on drivers/md/raid* · linux-raid@vger.kernel.org · Supported
- Kernel module
- raid10
Check it on the machine
grep -wE 'CONFIG_MD|CONFIG_MD_RAID10' /boot/config-$(uname -r)Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.
lsmod | grep -w raid10Prints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.
Show whether Debian builds this, per release
Debian builds this as a loadable module. Every release below compiles it as a module on every flavour, so whether the code is in the running kernel depends on whether that module is loaded.
- bookworm, trixie, forky, sid, bookworm · linux-6.12m
- m
- a loadable module on every flavour - check lsmod, can be blacklisted
- Build switches
- CONFIG_MD, CONFIG_MD_RAID10
- Reads as
- all on means the file is compiled; any one off means it is not.
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages
Signals
- Published
- 2026-08-15 (2 months ago)source
- CVSS
- 7.5 high
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsource recompute it - Attack vector
- network (AV:N)source
- EPSS
- 0.46%, higher than 38.5% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/md
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 5.17 | 6.12.111 | fea339685925 |
| 5.17 | 6.18.53 | 11b35d1906a7 |
| 5.17 | 7.1.5 | d1324b41dabd |
| 5.17 | 7.2 | 393d687131d8 |
| 5.15.111 | 0 | 0 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4817-1 | 2026-10-04 | bookworm 6.12.111-1~deb12u1 | tracker |
| DSA-6528-1 | 2026-09-29 | trixie 6.12.111-1 | tracker |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:NAttack vector, network
- RAID10 is commonly used on network-facing storage servers; discard/TRIM/UNMAP from remote iSCSI initiators or NFS clients reaches raid10_make_request() through the block layer without local host login.
- AC:LAttack complexity, low
- An attacker can reliably trigger the bug by issuing large, stripe-misaligned discards to force bio_split() and inducing GFP_NOIO allocation failure via self-created memory pressure; no rare timing or victim state is required.
- PR:NPrivileges required, none
- Exploitation requires only network reachability to a storage service that accepts discard/UNMAP/DEALLOCATE on the RAID10 LUN or exported filesystem, not Linux host administrator privileges or capabilities.
- UI:NUser interaction, none
- Discard, TRIM, punch-hole, and SCSI UNMAP are programmatic storage operations that do not require any interactive action by a human victim beyond normal automated I/O.
- S:UScope, unchanged
- The leaked writes_pending and barrier/nr_pending counters only corrupt RAID10/md internal accounting within the kernel storage stack and do not cross VM, container, or IOMMU security boundaries.
- C:NConfidentiality impact, none
- The flaw is reference-count leakage on writes_pending and nr_pending with no out-of-bounds access, use-after-free, or memory disclosure; no confidential data is exposed.
- I:NIntegrity impact, none
- No memory corruption or unauthorized modification of user or filesystem data occurs; impact is limited to incorrect internal IO/barrier accounting rather than integrity compromise.
- A:HAvailability impact, high
- Leaked nr_pending prevents raise_barrier() and freeze_array() from ever completing, causing indefinite kernel thread hangs during recovery/reshape/error handling and persistent denial of storage service on the array.