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CVE-2026-74374
md/raid1,raid10: fix error-path detection with md_cloned_bio()
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-2026-74374 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 | vulnerable | 6.12.113-1 | No fix published anywhere yet, neither in Debian nor upstream for the series trixie tracks. Watch the Debian tracker page for this CVE. Advisories for trixie have historically landed a median of 11 days after publication. |
| 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. |
The vulnerability
What the bug is
Detect the error path using md_cloned_bio() instead of relying on r1_bio in raid1 or r10_bio->read_slot in raid10, which may be NULL or -1 after splitting and resubmitting a failed bio. As a result, the error path may not be recognized and memory allocations can incorrectly use GFP_NOIO instead of (GFP_NOIO | __GFP_HIGH), which can lead to a deadlock under memory pressure.
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/raid1.c
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
- raid1
Check it on the machine
grep -wE 'CONFIG_MD|CONFIG_MD_RAID1' /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 raid1Prints 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, sidm
- m
- a loadable module on every flavour - check lsmod, can be blacklisted
- Build switches
- CONFIG_MD, CONFIG_MD_RAID1
- 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
- 0.61%, higher than 48.1% 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 |
|---|---|---|
| 4.12 | 6.18.57 | 029b363c9b69 |
| 4.12 | 7.1.5 | 20fb582c92fd |
| 4.12 | 7.2 | 811545e0926d |
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
- Linux file/NAS servers commonly export md RAID1/RAID10 volumes via nfsd, ksmbd, or iSCSI; remote client reads reach md_submit_bio()→raid1/raid10_read_request(), and mirror read failures drive handle_read_error() on the blocked raid1d/raid10d thread without local shell access.
- AC:LAttack complexity, low
- An attacker can reliably hit the bug by reading sectors on a degraded mirror that return errors (common on production arrays), issuing large reads that bio_submit_split_bioset() splits on the error-retry path, and concurrently applying memory pressure so GFP_NOIO bio_alloc_clone() blocks reclaim while raid1d/raid10d holds the array frozen.
- PR:NPrivileges required, none
- Triggering the fault path requires only permission to read exported storage or files on an md-backed filesystem; no CAP_SYS_ADMIN, md ioctl, or init-namespace root is needed because read I/O and mirror error recovery run with no extra capability checks beyond normal block-device access.
- UI:NUser interaction, none
- No victim interaction is required; exploitation uses the attacker's own read I/O (or scripted NFS/SMB/iSCSI reads) together with memory pressure, without anyone mounting disks, acknowledging bad blocks, or performing other cooperative actions.
- S:UScope, unchanged
- The circular GFP_NOIO allocation wait while raid1d/raid10d is blocked in handle_read_error() freezes I/O within the same host kernel and md security domain; it does not cross VM, container, or IOMMU boundaries.
- C:NConfidentiality impact, none
- This is a GFP-flag misclassification causing reclaim/I/O circular wait (deadlock), not memory corruption, out-of-bounds access, use-after-free, or other primitives that could disclose kernel or user data.
- I:NIntegrity impact, none
- The flaw does not enable arbitrary writes, code execution, or silent data modification; impact is limited to blocking forward progress in the RAID error-recovery path under memory pressure.
- A:HAvailability impact, high
- Without __GFP_HIGH on the error path, bio_alloc_clone() can stall reclaim while raid1d/raid10d blocks with the array frozen, deadlocking all I/O to the md device and potentially hanging root/data volumes on enterprise RAID1/RAID10 servers.