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CVE-2026-74603
ptp: ocp: Fix board ID over-read
Published 2026-08-22 (2 months ago) by the Linux kernel CNA. Subsystem drivers/ptp. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-74603 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 | fixedDLA-4777-1 · 2026-09-08 · text | 6.1.187-1 | Update the kernel and reboot. DLA-4777-1 shipped the fix on 2026-09-08, in 6.1.187-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixedDSA-6466-1 · 2026-08-25 · text | 6.12.105-1 | Update the kernel and reboot. DSA-6466-1 shipped the fix on 2026-08-25, in 6.12.105-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.9-1 | Update the kernel and reboot. Fixed in 7.1.9-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.9-1 | Update the kernel and reboot. Fixed in 7.1.9-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4788-1 · 2026-09-19 · text | 6.12.107-1~deb12u1 | Update the kernel and reboot. DLA-4788-1 shipped the fix on 2026-09-19, in 6.12.107-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
The EEPROM board ID is a fixed 13-byte field and is not guaranteed to contain a NUL terminator. Passing it directly to devlink_info_version_fixed_put() treats it as a C string and may read beyond the field. Format at most OCP_BOARD_ID_LEN bytes into the existing local buffer before reporting the ID. Use a precision limit because the snprintf() output size alone does not bound the source string scan.
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/ptp/ptp_ocp.c
- What this is
- OPENCOMPUTE PTP CLOCK DRIVERMAINTAINERS section matched on drivers/ptp/ptp_ocp.c · netdev@vger.kernel.org · Maintained
- Kernel module
- ptp_ocp
Check it on the machine
grep -w CONFIG_PTP_1588_CLOCK_OCP /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 ptp_ocpPrints 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, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.
- bookwormMnot built on amd64/cloud-amd64, arm64/cloud-arm64, ppc64el/powerpc64le
- trixieMnot built on amd64/cloud-amd64, arm64/cloud-arm64, armel/rpi, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, s390x/s390x
- forky, sidMnot built on amd64/cloud-amd64, arm64/cloud-arm64, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, s390x/s390x
- bookworm · linux-6.12Mnot built on amd64/cloud-amd64, arm64/cloud-arm64, ppc64el/powerpc64le, ppc64el/powerpc64le-64k
- M
- a module where it is built at all; some flavours do not build it
- Build switch
- CONFIG_PTP_1588_CLOCK_OCP
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
- 2026-08-22 (2 months ago)source
- CVSS
- 7.1 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.13%, higher than 2.0% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/ptp
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 5.18 | 6.1.183 | 72ef3ce80078 |
| 5.18 | 6.6.152 | 3d965811be78 |
| 5.18 | 6.12.104 | f92558bbe78d |
| 5.18 | 6.18.45 | 5fd91dd4a143 |
| 5.18 | 7.1.9 | f8d7e5751267 |
| 5.18 | 7.2 | 6b69f2ef10cd |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4788-1 | 2026-09-19 | bookworm 6.12.107-1~deb12u1 | tracker |
| DLA-4777-1 | 2026-09-08 | bookworm 6.1.187-1 | tracker |
| DSA-6466-1 | 2026-08-25 | trixie 6.12.105-1 | 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:LAttack vector, local
- The vulnerable code is reached only through the devlink generic-netlink interface (DEVLINK_CMD_INFO_GET) via a local socket; ptp_ocp is a PCI PTP timecard driver with no network, Bluetooth, or physical-device input path to ptp_ocp_devlink_info_get().
- AC:LAttack complexity, low
- On a system with a probed OCP timecard, issuing devlink info deterministically calls ptp_ocp_devlink_info_get() and passes the 13-byte EEPROM board_id that is not guaranteed to be NUL-terminated, so the over-read is reliably triggered without races or attacker-uncontrollable layout.
- PR:LPrivileges required, low
- DEVLINK_CMD_INFO_GET is registered with only GENL_CMD_CAP_DO/GENL_CMD_CAP_DUMP and no GENL_ADMIN_PERM, and devlink_nl_pre_doit() adds no capability check, so any unprivileged local user with generic netlink access can invoke the vulnerable handler.
- UI:NUser interaction, none
- Exploitation requires only the attacker issuing a devlink info netlink request; no administrator or other user action is needed beyond the attacker having local access to the host.
- S:UScope, unchanged
- Kernel memory disclosure and any resulting crash are confined to the same host kernel; the bug does not cross VM, IOMMU, or sandbox security boundaries.
- C:HConfidentiality impact, high
- Passing the non-NUL-terminated board_id to devlink_info_version_fixed_put() makes devlink_info_version_put() and nla_put_string() use strlen(), reading past the 13-byte field through adjacent ptp_ocp/devlink private memory and returning leaked bytes in the netlink reply to the caller.
- I:NIntegrity impact, none
- The defect is purely an out-of-bounds kernel read with no write, heap corruption, or control-flow hijack primitive; only kernel memory is scanned and copied into the netlink response.
- A:HAvailability impact, high
- strlen() on the unterminated board_id can walk through subsequent kmalloc-backed struct fields and potentially past the devlink private allocation, touching unmapped pages and oopsing/panicking the kernel; an unprivileged user can repeat the devlink info query to retrigger it.