high 7.8

CVE-2025-38346 json

ftrace: Fix UAF when lookup kallsym after ftrace disabled

published 2025-07-10 16 mo ago modified 2026-10-15 24 d ago also EUVD-2025-20900

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 10%
public exploits: 0; none known

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

The following issue happens with a buggy module:

BUG: unable to handle page fault for address: ffffffffc05d0218 PGD 1bd66f067 P4D 1bd66f067 PUD 1bd671067 PMD 101808067 PTE 0 Oops: Oops: 0000 [#1] SMP KASAN PTI Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS RIP: 0010:sized_strscpy+0x81/0x2f0 RSP: 0018:ffff88812d76fa08 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffffffffc0601010 RCX: dffffc0000000000 RDX: 0000000000000038 RSI: dffffc0000000000 RDI: ffff88812608da2d RBP: 8080808080808080 R08: ffff88812608da2d R09: ffff88812608da68 R10: ffff88812608d82d R11: ffff88812608d810 R12: 0000000000000038 R13: ffff88812608da2d R14: ffffffffc05d0218 R15: fefefefefefefeff FS: 00007fef552de740(0000) GS:ffff8884251c7000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffc05d0218 CR3: 00000001146f0000 CR4: 00000000000006f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> ftrace_mod_get_kallsym+0x1ac/0x590 update_iter_mod+0x239/0x5b0 s_next+0x5b/0xa0 seq_read_iter+0x8c9/0x1070 seq_read+0x249/0x3b0 proc_reg_read+0x1b0/0x280 vfs_read+0x17f/0x920 ksys_read+0xf3/0x1c0 do_syscall_64+0x5f/0x2e0 entry_SYSCALL_64_after_hwframe+0x76/0x7e

The above issue may happen as follows: (1) Add kprobe tracepoint; (2) insmod test.ko; (3) Module triggers ftrace disabled; (4) rmmod test.ko; (5) cat /proc/kallsyms; --> Will trigger UAF as test.ko already removed; ftrace_mod_get_kallsym() ... strscpy(module_name, mod_map->mod->name, MODULE_NAME_LEN); ...

The problem is when a module triggers an issue with ftrace and sets ftrace_disable. The ftrace_disable is set when an anomaly is discovered and to prevent any more damage, ftrace stops all text modification. The issue that happened was that the ftrace_disable stops more than just the text modification.

When a module is loaded, its init functions can also be traced. Because kallsyms deletes the init functions after a module has loaded, ftrace saves them when the module is loaded and function tracing is enabled. This allows the output of the function trace to show the init function names instead of just their raw memory addresses.

When a module is removed, ftrace_release_mod() is called, and if ftrace_disable is set, it just returns without doing anything more. The problem here is that it leaves the mod_list still around and if kallsyms is called, it will call into this code and access the module memory that has already been freed as it will return:

strscpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);

Where the "mod" no longer exists and triggers a UAF bug.

Patch / fix

fixed in 1 distros 5 links 8

Linux Linux 5.4.295, 5.10.239, 5.15.186, 6.1.142, 6.6.95, 6.12.35, 6.15.4, 6.16

debian ubuntu red hat almalinux azure linux

linux Debian 12 6.1.147-1
linux Debian 14, Debian 13 6.12.35-1

debian advisories DEBIAN-CVE-2025-38346

linux Ubuntu 22.04 LTS 5.15.0-156.166
linux Ubuntu 24.04 LTS 6.8.0-100.100
linux-aws Ubuntu 22.04 LTS 5.15.0-1092.99
linux-aws Ubuntu 24.04 LTS 6.8.0-1046.49
linux-gcp Ubuntu 22.04 LTS 5.15.0-1092.101
linux-gcp Ubuntu 24.04 LTS 6.8.0-1047.50
linux-gke Ubuntu 22.04 LTS 5.15.0-1089.95
linux-gke Ubuntu 24.04 LTS 6.8.0-1043.48

ubuntu advisories UBUNTU-CVE-2025-38346

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

kernel RHEL 10.2 6.12.0-211.7.1.el10_2
rv RHEL 10.2 6.12.0-211.7.1.el10_2
perf RHEL 10.2 6.12.0-211.7.1.el10_2
rtla RHEL 10.2 6.12.0-211.7.1.el10_2
libperf RHEL 10.2 6.12.0-211.7.1.el10_2
kernel-rt RHEL 10.2 6.12.0-211.7.1.el10_2
kernel-64k RHEL 10.2 6.12.0-211.7.1.el10_2
kernel-core RHEL 10.2 6.12.0-211.7.1.el10_2

red hat advisories RHSA-2026:18134

kernel AlmaLinux 10 6.12.0-211.7.1.el10_2
rv AlmaLinux 10 6.12.0-211.7.1.el10_2
perf AlmaLinux 10 6.12.0-211.7.1.el10_2
rtla AlmaLinux 10 6.12.0-211.7.1.el10_2
libperf AlmaLinux 10 6.12.0-211.7.1.el10_2
kernel-rt AlmaLinux 10 6.12.0-211.7.1.el10_2
kernel-64k AlmaLinux 10 6.12.0-211.7.1.el10_2
kernel-core AlmaLinux 10 6.12.0-211.7.1.el10_2

almalinux advisories ALSA-2026:18134

kernel Azure Linux 3.0 6.6.96.1-1

azure linux advisories AZL-64914

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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-2025-38346 updated 2026-11-05 cvss 5.5

kernel: ftrace: Fix UAF when lookup kallsym after ftrace disabled

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
affected: no fix available “Fix deferred”
Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.7.1.el10_2, perf 6.12.0-211.7.1.el10_2, rtla 6.12.0-211.7.1.el10_2, python3-perf 6.12.0-211.7.1.el10_2, kernel-devel-matched 6.12.0-211.7.1.el10_2, kernel-64k-devel-matched 6.12.0-211.7.1.el10_2, +7 more Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.7.1.el10_2, kernel-64k 6.12.0-211.7.1.el10_2, kernel-core 6.12.0-211.7.1.el10_2, kernel-tools 6.12.0-211.7.1.el10_2, kernel-modules 6.12.0-211.7.1.el10_2, kernel-64k-core 6.12.0-211.7.1.el10_2, +28 more Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.7.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.7.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.7.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.7.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.7.1.el10_2 Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.7.1.el10_2, kernel-rt-64k 6.12.0-211.7.1.el10_2, kernel-rt-core 6.12.0-211.7.1.el10_2, kernel-rt-modules 6.12.0-211.7.1.el10_2, kernel-rt-64k-core 6.12.0-211.7.1.el10_2, kernel-rt-debug-core 6.12.0-211.7.1.el10_2, +14 more Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.7.1.el10_2, kernel-rt-core 6.12.0-211.7.1.el10_2, kernel-rt-modules 6.12.0-211.7.1.el10_2, kernel-rt-debug-core 6.12.0-211.7.1.el10_2, kernel-rt-modules-core 6.12.0-211.7.1.el10_2, kernel-rt-debug-modules 6.12.0-211.7.1.el10_2, +4 more
fixed: vendor fix RHSA-2026:18134
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
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

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 24 d ago (2026-10-15)

Exploit prediction

0.20% chance of exploitation in the next 30 days, higher than 10% of all scored CVEs (FIRST EPSS, 2026-11-08).

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
NVD	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

CWE-416 Use After Free

Technology feeds

Linux kernel rss critical rss

References

Sources

CVE List CVE-2025-38346
NVD CVE-2025-38346

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.

Summary