CVE-2022-50536 [High] | Use-After-Free in Linux Kernel

In the Linux kernel, the following vulnerability has been resolved: bpf, sockmap: Fix repeated calls to sock_put() when msg has more_data In tcp_bpf_send_verdict() redirection, the eval variable is assigned to __SK_REDIRECT after the apply_bytes data is sent, if msg has more_data, sock_put() will be called multiple times. We should reset the eval variable to __SK_NONE every time more_data starts. This causes: IPv4: Attempt to release TCP socket in state 1 00000000b4c925d7 ------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 5 PID: 4482 at lib/refcount.c:25 refcount_warn_saturate+0x7d/0x110 Modules linked in: CPU: 5 PID: 4482 Comm: sockhash_bypass Kdump: loaded Not tainted 6.0.0 #1 Hardware name: Red Hat KVM, BIOS 1.11.0-2.el7 04/01/2014 Call Trace: <TASK> __tcp_transmit_skb+0xa1b/0xb90 ? __alloc_skb+0x8c/0x1a0 ? __kmalloc_node_track_caller+0x184/0x320 tcp_write_xmit+0x22a/0x1110 __tcp_push_pending_frames+0x32/0xf0 do_tcp_sendpages+0x62d/0x640 tcp_bpf_push+0xae/0x2c0 tcp_bpf_sendmsg_redir+0x260/0x410 ? preempt_count_add+0x70/0xa0 tcp_bpf_send_verdict+0x386/0x4b0 tcp_bpf_sendmsg+0x21b/0x3b0 sock_sendmsg+0x58/0x70 __sys_sendto+0xfa/0x170 ? xfd_validate_state+0x1d/0x80 ? switch_fpu_return+0x59/0xe0 __x64_sys_sendto+0x24/0x30 do_syscall_64+0x37/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2025-10-08	—	0.02%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2025-10-08

—

0.02%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
7.8	3.1	HIGH	`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	1.8	5.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

7.8

3.1

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

1.8

5.9

[email protected]

OS Trackers for CVE-2022-50536

vendor	priority	summary	link
`debian`	not yet assigned	CVE-2022-50536 not yet assigned 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-2022-50536
`redhat`	medium	—	https://access.redhat.com/security/cve/CVE-2022-50536
`suse`	medium	CVE-2022-50536 severity moderate: SUSE including 85 source package names (bpftool-4.18.0-372.9.1.el8, bpftool-7.2.0-362.8.1.el9_3, …), 331 product×package rows across 60 product lines (Image SLES12-SP5-Azure-BYOS, Image SLES12-SP5-Azure-HPC-BYOS, … (60 product lines)): Known Not Affected 212, Fixed 119.	https://www.suse.com/security/cve/CVE-2022-50536/
`ubuntu`	medium	CVE-2022-50536 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, ignored 162, released 134, not-affected 80, needed 20, needs-triage 1.	https://ubuntu.com/security/CVE-2022-50536

Affected software / configurations for CVE-2022-50536

Vendor	Product	Version	Raw CPE
linux	linux_kernel	>= 5.4.157, < 5.4.229	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.10.77, < 5.10.163	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.14.16, < 5.15	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.15.1, < 5.15.86	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.16, < 6.0.16	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 6.1, < 6.1.2	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	5.15	cpe:2.3:o:linux:linux_kernel:5.15:-::::::

References for CVE-2022-50536

URL	Tags
https://git.kernel.org/stable/c/113236e8f49f262f318c00ebb14b15f4834e87c1	Patch
https://git.kernel.org/stable/c/28e4a763cd4a2b1a78852216ef4bd7df3a05cec6	Patch
https://git.kernel.org/stable/c/578a7628b838a3ac8ad61deaab5a816ff032ac13	Patch
https://git.kernel.org/stable/c/7508b9f4daac4ec7dfe0b6fb2d688b1c1c105e10	Patch
https://git.kernel.org/stable/c/7a9841ca025275b5b0edfb0b618934abb6ceec15	Patch
https://git.kernel.org/stable/c/8786bde11a4f31b63b3036731df0b47337a7a245	Patch

URL

CVE-2022-50536 | bpf, sockmap: Fix repeated calls to sock_put() when msg has more_data

Exploit prediction scoring system (EPSS) score for CVE-2022-50536

Common vulnerability scoring system (CVSS) metrics for CVE-2022-50536

Weakness enumeration for CVE-2022-50536

OS Trackers for CVE-2022-50536

Affected software / configurations for CVE-2022-50536

References for CVE-2022-50536