CVE-2025-38528 [Medium] | Security Vulnerability in Linux Kernel

In the Linux kernel, the following vulnerability has been resolved: bpf: Reject %p% format string in bprintf-like helpers static const char fmt[] = "%p%"; bpf_trace_printk(fmt, sizeof(fmt)); The above BPF program isn't rejected and causes a kernel warning at runtime: Please remove unsupported %\x00 in format string WARNING: CPU: 1 PID: 7244 at lib/vsprintf.c:2680 format_decode+0x49c/0x5d0 This happens because bpf_bprintf_prepare skips over the second %, detected as punctuation, while processing %p. This patch fixes it by not skipping over punctuation. %\x00 is then processed in the next iteration and rejected.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2025-08-16	—	0.02%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2025-08-16

—

0.02%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
5.5	3.1	MEDIUM	`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H` Click to expand Attack vector (AV:L) They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:L) A normal user session is enough; they don’t have to be admin. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	1.8	3.6	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

5.5

3.1

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand

Attack vector (AV:L): They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L): A normal user session is enough; they don’t have to be admin.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

1.8

3.6

[email protected]

OS Trackers for CVE-2025-38528

vendor	priority	summary	link
`debian`	unimportant	CVE-2025-38528 unimportant priority: Debian including 2 source packages (linux, linux-6.1), 6 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 6.	https://security-tracker.debian.org/tracker/CVE-2025-38528
`redhat`	low	—	https://access.redhat.com/security/cve/CVE-2025-38528
`suse`	medium	CVE-2025-38528 severity moderate: SUSE including 476 source package names (2.1.3-6.73:kernel-default-base-6.4.0-34.1.21.11, 2.1.3-7.50:kernel-default-6.4.0-34.1, …), 985 product×package rows across 198 product lines (Container suse/sl-micro/6.0/base-os-container, Container suse/sl-micro/6.0/kvm-os-container, … (198 product lines)): Fixed 627, Known Affected 231, Known Not Affected 106, First Fixed 21.	https://www.suse.com/security/cve/CVE-2025-38528/
`ubuntu`	medium	CVE-2025-38528 medium priority: Ubuntu including 158 source packages (linux, linux-allwinner-5.19, …), 1414 status rows across 9 suites (bionic, focal, jammy, noble, plucky, questing, trusty, upstream, xenial): DNE 1017, released 165, ignored 161, not-affected 63, needed 4, needs-triage 2, pending 2.	https://ubuntu.com/security/CVE-2025-38528

Affected software / configurations for CVE-2025-38528

Vendor	Product	Version	Raw CPE
linux	linux_kernel	>= 5.13, < 5.15.190	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.16, < 6.1.147	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 6.2, < 6.6.100	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 6.7, < 6.12.40	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 6.13, < 6.15.8	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	6.16	cpe:2.3:o:linux:linux_kernel:6.16:rc1::::::
linux	linux_kernel	6.16	cpe:2.3:o:linux:linux_kernel:6.16:rc2::::::
linux	linux_kernel	6.16	cpe:2.3:o:linux:linux_kernel:6.16:rc3::::::
linux	linux_kernel	6.16	cpe:2.3:o:linux:linux_kernel:6.16:rc4::::::
linux	linux_kernel	6.16	cpe:2.3:o:linux:linux_kernel:6.16:rc5::::::
linux	linux_kernel	6.16	cpe:2.3:o:linux:linux_kernel:6.16:rc6::::::
debian	debian_linux	11.0	cpe:2.3:o:debian:debian_linux:11.0:::::::*

References for CVE-2025-38528

URL	Tags
https://git.kernel.org/stable/c/1c5f5fd47bbda17cb885fe6f03730702cd53d3f8	Patch
https://git.kernel.org/stable/c/61d5fa45ed13e42af14c7e959baba9908b8ee6d4	Patch
https://git.kernel.org/stable/c/6952aeace93f8c9ea01849efecac24dd3152c9c9	Patch
https://git.kernel.org/stable/c/97303e541e12f1fea97834ec64b98991e8775f39	Patch
https://git.kernel.org/stable/c/e7be679124bae8cf4fa6e40d7e1661baddfb3289	Patch
https://git.kernel.org/stable/c/f8242745871f81a3ac37f9f51853d12854fd0b58	Patch
https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html	Mailing List Third Party Advisory

URL

CVE-2025-38528 | bpf: Reject %p% format string in bprintf-like helpers

Exploit prediction scoring system (EPSS) score for CVE-2025-38528

Common vulnerability scoring system (CVSS) metrics for CVE-2025-38528

Weakness enumeration for CVE-2025-38528

OS Trackers for CVE-2025-38528

Affected software / configurations for CVE-2025-38528

References for CVE-2025-38528