CVE-2025-38165 [Medium] | Security Vulnerability in Linux Kernel

In the Linux kernel, the following vulnerability has been resolved: bpf, sockmap: Fix panic when calling skb_linearize The panic can be reproduced by executing the command: ./bench sockmap -c 2 -p 1 -a --rx-verdict-ingress --rx-strp 100000 Then a kernel panic was captured: ''' [ 657.460555] kernel BUG at net/core/skbuff.c:2178! [ 657.462680] Tainted: [W]=WARN [ 657.463287] Workqueue: events sk_psock_backlog ... [ 657.469610] <TASK> [ 657.469738] ? die+0x36/0x90 [ 657.469916] ? do_trap+0x1d0/0x270 [ 657.470118] ? pskb_expand_head+0x612/0xf40 [ 657.470376] ? pskb_expand_head+0x612/0xf40 [ 657.470620] ? do_error_trap+0xa3/0x170 [ 657.470846] ? pskb_expand_head+0x612/0xf40 [ 657.471092] ? handle_invalid_op+0x2c/0x40 [ 657.471335] ? pskb_expand_head+0x612/0xf40 [ 657.471579] ? exc_invalid_op+0x2d/0x40 [ 657.471805] ? asm_exc_invalid_op+0x1a/0x20 [ 657.472052] ? pskb_expand_head+0xd1/0xf40 [ 657.472292] ? pskb_expand_head+0x612/0xf40 [ 657.472540] ? lock_acquire+0x18f/0x4e0 [ 657.472766] ? find_held_lock+0x2d/0x110 [ 657.472999] ? __pfx_pskb_expand_head+0x10/0x10 [ 657.473263] ? __kmalloc_cache_noprof+0x5b/0x470 [ 657.473537] ? __pfx___lock_release.isra.0+0x10/0x10 [ 657.473826] __pskb_pull_tail+0xfd/0x1d20 [ 657.474062] ? __kasan_slab_alloc+0x4e/0x90 [ 657.474707] sk_psock_skb_ingress_enqueue+0x3bf/0x510 [ 657.475392] ? __kasan_kmalloc+0xaa/0xb0 [ 657.476010] sk_psock_backlog+0x5cf/0xd70 [ 657.476637] process_one_work+0x858/0x1a20 ''' The panic originates from the assertion BUG_ON(skb_shared(skb)) in skb_linearize(). A previous commit(see Fixes tag) introduced skb_get() to avoid race conditions between skb operations in the backlog and skb release in the recvmsg path. However, this caused the panic to always occur when skb_linearize is executed. The "--rx-strp 100000" parameter forces the RX path to use the strparser module which aggregates data until it reaches 100KB before calling sockmap logic. The 100KB payload exceeds MAX_MSG_FRAGS, triggering skb_linearize. To fix this issue, just move skb_get into sk_psock_skb_ingress_enqueue. ''' sk_psock_backlog: sk_psock_handle_skb skb_get(skb) <== we move it into 'sk_psock_skb_ingress_enqueue' sk_psock_skb_ingress____________ ↓ | | → sk_psock_skb_ingress_self | sk_psock_skb_ingress_enqueue sk_psock_verdict_apply_________________↑ skb_linearize ''' Note that for verdict_apply path, the skb_get operation is unnecessary so we add 'take_ref' param to control it's behavior.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-04-29	0.04%	0.10%	+0.06%
2	2025-12-18	0.06%	0.04%	-0.01%
3	2025-12-11	—	0.06%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-04-29

0.04%

0.10%

+0.06%

2025-12-18

0.06%

0.04%

-0.01%

2025-12-11

—

0.06%

—

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-2025-38165

vendor	priority	summary	link
`debian`	unimportant	CVE-2025-38165 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-2025-38165
`redhat`	medium	—	https://access.redhat.com/security/cve/CVE-2025-38165
`suse`	medium	CVE-2025-38165 severity moderate: SUSE including 244 source package names (2.1.3-6.67:kernel-default-base-6.4.0-32.1.21.10, 2.1.3-7.44:kernel-default-6.4.0-32.1, …), 860 product×package rows across 216 product lines (Container suse/sl-micro/6.0/base-os-container, Container suse/sl-micro/6.0/kvm-os-container, … (216 product lines)): Fixed 627, Known Not Affected 212, First Fixed 21.	https://www.suse.com/security/cve/CVE-2025-38165/
`ubuntu`	medium	CVE-2025-38165 medium priority: Ubuntu including 158 source packages (linux, linux-allwinner-5.19, …), 1551 status rows across 10 suites (bionic, focal, jammy, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 1145, released 169, ignored 164, not-affected 67, needed 3, needs-triage 2, pending 1.	https://ubuntu.com/security/CVE-2025-38165

Affected software / configurations for CVE-2025-38165

Vendor	Product	Version	Raw CPE
linux	linux_kernel	>= 6.1.54, < 6.1.142	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 6.5.4, < 6.6.94	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 6.7, < 6.12.34	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 6.13, < 6.15.3	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	5.15.189	cpe:2.3:o:linux:linux_kernel:5.15.189:::::::*
debian	debian_linux	11.0	cpe:2.3:o:debian:debian_linux:11.0:::::::*

References for CVE-2025-38165

URL	Tags
https://git.kernel.org/stable/c/3d25fa2d7f127348c818e1dab9e58534f7ac56cc	Patch
https://git.kernel.org/stable/c/4dba44333a11522df54b49aa1f2edfaf6ce35fc7	Patch
https://git.kernel.org/stable/c/5ca2e29f6834c64c0e5a9ccf1278c21fb49b827e	Patch
https://git.kernel.org/stable/c/9718ba6490732dbe70190d42c21deb1440834402	Patch
https://git.kernel.org/stable/c/db1d15a26f21f97459508c42ae87cabe8d3afc3b	Patch
https://git.kernel.org/stable/c/e9c1299d813fc04668042690f2c3cc76d013959a	Patch
https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html	Third Party Advisory

URL

CVE-2025-38165 | bpf, sockmap: Fix panic when calling skb_linearize

Exploit prediction scoring system (EPSS) score for CVE-2025-38165

Common vulnerability scoring system (CVSS) metrics for CVE-2025-38165

Weakness enumeration for CVE-2025-38165

OS Trackers for CVE-2025-38165

Affected software / configurations for CVE-2025-38165

References for CVE-2025-38165