CVE-2025-38528

bpf: Reject %p% format string in bprintf-like helpers

State: Published
Severity: 7.1 High
Published: Aug 16, 2025
Updated: Oct 15, 2026
Reserved: Apr 16, 2025

Description

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.

Scores

CVSS	Score	Vector	Source
3.1	7.1 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H	Linux

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	48cac3f4a96ddf08df8e53809ed066de0dc93915 to before 97303e541e12f1fea97834ec64b98991e8775f39Affected 48cac3f4a96ddf08df8e53809ed066de0dc93915 to before 61d5fa45ed13e42af14c7e959baba9908b8ee6d4Affected 48cac3f4a96ddf08df8e53809ed066de0dc93915 to before e7be679124bae8cf4fa6e40d7e1661baddfb3289Affected 48cac3f4a96ddf08df8e53809ed066de0dc93915 to before 6952aeace93f8c9ea01849efecac24dd3152c9c9Affected 48cac3f4a96ddf08df8e53809ed066de0dc93915 to before 1c5f5fd47bbda17cb885fe6f03730702cd53d3f8Affected 48cac3f4a96ddf08df8e53809ed066de0dc93915 to before f8242745871f81a3ac37f9f51853d12854fd0b58Affected
LinuxLinux	5.13Affected before 5.13Not affected 5.15.190 through 5.15.Not affected 6.1.147 through 6.1.Not affected 6.6.100 through 6.6.Not affected 6.12.40 through 6.12.Not affected 6.15.8 through 6.15.*Not affected 6.16 and laterNot affected

Product

Versions

LinuxLinux

48cac3f4a96ddf08df8e53809ed066de0dc93915 to before 97303e541e12f1fea97834ec64b98991e8775f39Affected
48cac3f4a96ddf08df8e53809ed066de0dc93915 to before 61d5fa45ed13e42af14c7e959baba9908b8ee6d4Affected
48cac3f4a96ddf08df8e53809ed066de0dc93915 to before e7be679124bae8cf4fa6e40d7e1661baddfb3289Affected
48cac3f4a96ddf08df8e53809ed066de0dc93915 to before 6952aeace93f8c9ea01849efecac24dd3152c9c9Affected
48cac3f4a96ddf08df8e53809ed066de0dc93915 to before 1c5f5fd47bbda17cb885fe6f03730702cd53d3f8Affected
48cac3f4a96ddf08df8e53809ed066de0dc93915 to before f8242745871f81a3ac37f9f51853d12854fd0b58Affected

LinuxLinux

5.13Affected
before 5.13Not affected
5.15.190 through 5.15.*Not affected
6.1.147 through 6.1.*Not affected
6.6.100 through 6.6.*Not affected
6.12.40 through 6.12.*Not affected
6.15.8 through 6.15.*Not affected
6.16 and laterNot affected

References

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