Skip to content
Fencer Vulns
medium 5.5

CVE-2026-53095 json

bpf: Fix abuse of kprobe_write_ctx via freplace

published 2026-06-24 4 mo ago modified 2026-07-21 3 mo ago also EUVD-2026-38963

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 5%
public exploits
0
none known

Summary

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

bpf: Fix abuse of kprobe_write_ctx via freplace

uprobe programs are allowed to modify struct pt_regs.

Since the actual program type of uprobe is KPROBE, it can be abused to modify struct pt_regs via kprobe+freplace when the kprobe attaches to kernel functions.

For example,

SEC("?kprobe") int kprobe(struct pt_regs *regs) { return 0; }

SEC("?freplace") int freplace_kprobe(struct pt_regs *regs) { regs->di = 0; return 0; }

freplace_kprobe prog will attach to kprobe prog. kprobe prog will attach to a kernel function.

Without this patch, when the kernel function runs, its first arg will always be set as 0 via the freplace_kprobe prog.

To fix the abuse of kprobe_write_ctx=true via kprobe+freplace, disallow attaching freplace programs on kprobe programs with different kprobe_write_ctx values.

Patch / fix

  • Linux Linux 6.18.33, 7.0.10, 7.1
  • linux Debian 14 7.0.10-1

debian advisories DEBIAN-CVE-2026-53095

  • 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-2026-53095

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

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-2026-53095 updated cvss 6.4

kernel: bpf: Fix abuse of kprobe_write_ctx via freplace

  • 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

0.16% chance of exploitation in the next 30 days, higher than 5% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns 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.