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Fencer Intel
high 7.8

CVE-2026-53025 json

greybus: raw: fix use-after-free on cdev close

published 4mo ago modified 12d ago also EUVD-2026-38893

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 6%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

greybus: raw: fix use-after-free on cdev close

This addresses a use-after-free bug when a raw bundle is disconnected but its chardev is still opened by an application. When the application releases the cdev, it causes the following panic when init on free is enabled (CONFIG_INIT_ON_FREE_DEFAULT_ON=y):

refcount_t: underflow; use-after-free. WARNING: CPU: 0 PID: 139 at lib/refcount.c:28 refcount_warn_saturate+0xd0/0x130 ... Call Trace: <TASK> cdev_put+0x18/0x30 __fput+0x255/0x2a0 __x64_sys_close+0x3d/0x80 do_syscall_64+0xa4/0x290 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The cdev is contained in the "gb_raw" structure, which is freed in the disconnect operation. When the cdev is released at a later time, cdev_put gets an address that points to freed memory.

To fix this use-after-free, convert the struct device from a pointer to being embedded, that makes the lifetime of the cdev and of this device the same. Then, use cdev_device_add, which guarantees that the device won't be released until all references to the cdev have been released. Finally, delegate the freeing of the structure to the device release function, instead of freeing immediately in the disconnect callback.

Patch / fix

  • Linux Linux 6.1.191, 6.6.160, 6.12.114, 6.18.57, 7.0.10, 7.1
  • linux Debian 13 6.12.115-2
  • linux Debian 14 7.0.10-1

debian advisories DEBIAN-CVE-2026-53025

  • linux Ubuntu 26.04 LTS 7.0.0-28.28
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1009.9
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1008.8
  • linux-gke Ubuntu 26.04 LTS 7.0.0-1003.4
  • linux-ibm Ubuntu 26.04 LTS 7.0.0-1010.10
  • linux-azure Ubuntu 26.04 LTS 7.0.0-1010.10
  • linux-raspi Ubuntu 26.04 LTS 7.0.0-1015.15
  • linux-riscv Ubuntu 26.04 LTS 7.0.0-28.28.1

ubuntu advisories UBUNTU-CVE-2026-53025

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Is CVE-2026-53025 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-53025 updated

kernel: greybus: raw: fix use-after-free on cdev close

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.17% chance of exploitation in the next 30 days, higher than 6% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Weakness
Technology feeds

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.