CVE-2025-21889 [Medium] | Security Vulnerability in Linux Kernel

In the Linux kernel, the following vulnerability has been resolved: perf/core: Add RCU read lock protection to perf_iterate_ctx() The perf_iterate_ctx() function performs RCU list traversal but currently lacks RCU read lock protection. This causes lockdep warnings when running perf probe with unshare(1) under CONFIG_PROVE_RCU_LIST=y: WARNING: suspicious RCU usage kernel/events/core.c:8168 RCU-list traversed in non-reader section!! Call Trace: lockdep_rcu_suspicious ? perf_event_addr_filters_apply perf_iterate_ctx perf_event_exec begin_new_exec ? load_elf_phdrs load_elf_binary ? lock_acquire ? find_held_lock ? bprm_execve bprm_execve do_execveat_common.isra.0 __x64_sys_execve do_syscall_64 entry_SYSCALL_64_after_hwframe This protection was previously present but was removed in commit bd2756811766 ("perf: Rewrite core context handling"). Add back the necessary rcu_read_lock()/rcu_read_unlock() pair around perf_iterate_ctx() call in perf_event_exec(). [ mingo: Use scoped_guard() as suggested by Peter ]

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-05-05	0.07%	0.02%	-0.05%
2	2026-01-21	0.02%	0.07%	+0.05%
3	2025-03-28	—	0.02%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-05-05

0.07%

0.02%

-0.05%

2026-01-21

0.02%

0.07%

+0.05%

2025-03-28

—

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-2025-21889

vendor	priority	summary	link
`debian`	unimportant	CVE-2025-21889 unimportant priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5.	https://security-tracker.debian.org/tracker/CVE-2025-21889
`redhat`	low	—	https://access.redhat.com/security/cve/CVE-2025-21889
`suse`	medium	—	https://www.suse.com/security/cve/CVE-2025-21889/
`ubuntu`	medium	CVE-2025-21889 medium priority: Ubuntu including 150 source packages (linux, linux-allwinner-5.19, …), 1487 status rows across 10 suites (bionic, focal, jammy, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 1097, ignored 150, released 130, not-affected 110.	https://ubuntu.com/security/CVE-2025-21889

Affected software / configurations for CVE-2025-21889

Vendor	Product	Version	Raw CPE
linux	linux_kernel	>= 6.2, < 6.6.81	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 6.7, < 6.12.18	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 6.13, < 6.13.6	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	6.14	cpe:2.3:o:linux:linux_kernel:6.14:rc1::::::
linux	linux_kernel	6.14	cpe:2.3:o:linux:linux_kernel:6.14:rc2::::::
linux	linux_kernel	6.14	cpe:2.3:o:linux:linux_kernel:6.14:rc3::::::
linux	linux_kernel	6.14	cpe:2.3:o:linux:linux_kernel:6.14:rc4::::::

References for CVE-2025-21889

URL	Tags
https://git.kernel.org/stable/c/0fe8813baf4b2e865d3b2c735ce1a15b86002c74	Patch
https://git.kernel.org/stable/c/a2475ccad6120546ea45dbcd6cd1f74dc565ef6b	Patch
https://git.kernel.org/stable/c/dd536566dda9a551fc2a2acfab5313a5bb13ed02	Patch
https://git.kernel.org/stable/c/f390c2eea571945f357a2d3b9fcb1c015767132e	Patch

URL

CVE-2025-21889 | perf/core: Add RCU read lock protection to perf_iterate_ctx()

Exploit prediction scoring system (EPSS) score for CVE-2025-21889

Common vulnerability scoring system (CVSS) metrics for CVE-2025-21889

Weakness enumeration for CVE-2025-21889

OS Trackers for CVE-2025-21889

Affected software / configurations for CVE-2025-21889

References for CVE-2025-21889