CVE-2022-49958 [Medium] | Information Disclosure in Linux Kernel

In the Linux kernel, the following vulnerability has been resolved: net/sched: fix netdevice reference leaks in attach_default_qdiscs() In attach_default_qdiscs(), if a dev has multiple queues and queue 0 fails to attach qdisc because there is no memory in attach_one_default_qdisc(). Then dev->qdisc will be noop_qdisc by default. But the other queues may be able to successfully attach to default qdisc. In this case, the fallback to noqueue process will be triggered. If the original attached qdisc is not released and a new one is directly attached, this will cause netdevice reference leaks. The following is the bug log: veth0: default qdisc (fq_codel) fail, fallback to noqueue unregister_netdevice: waiting for veth0 to become free. Usage count = 32 leaked reference. qdisc_alloc+0x12e/0x210 qdisc_create_dflt+0x62/0x140 attach_one_default_qdisc.constprop.41+0x44/0x70 dev_activate+0x128/0x290 __dev_open+0x12a/0x190 __dev_change_flags+0x1a2/0x1f0 dev_change_flags+0x23/0x60 do_setlink+0x332/0x1150 __rtnl_newlink+0x52f/0x8e0 rtnl_newlink+0x43/0x70 rtnetlink_rcv_msg+0x140/0x3b0 netlink_rcv_skb+0x50/0x100 netlink_unicast+0x1bb/0x290 netlink_sendmsg+0x37c/0x4e0 sock_sendmsg+0x5f/0x70 ____sys_sendmsg+0x208/0x280 Fix this bug by clearing any non-noop qdiscs that may have been assigned before trying to re-attach.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-04-14	0.02%	0.07%	+0.05%
2	2025-06-18	—	0.02%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-04-14

0.02%

0.07%

+0.05%

2025-06-18

—

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-2022-49958

vendor	priority	summary	link
`debian`	not yet assigned	CVE-2022-49958 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-2022-49958
`redhat`	medium	—	https://access.redhat.com/security/cve/CVE-2022-49958
`suse`	medium	—	https://www.suse.com/security/cve/CVE-2022-49958/
`ubuntu`	medium	CVE-2022-49958 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, ignored 147, not-affected 144, released 114, needs-triage 1.	https://ubuntu.com/security/CVE-2022-49958

Affected software / configurations for CVE-2022-49958

Vendor	Product	Version	Raw CPE
linux	linux_kernel	>= 5.8, < 5.10.142	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.11, < 5.15.66	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.16, < 5.19.8	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	6.0	cpe:2.3:o:linux:linux_kernel:6.0:rc1::::::
linux	linux_kernel	6.0	cpe:2.3:o:linux:linux_kernel:6.0:rc2::::::
linux	linux_kernel	6.0	cpe:2.3:o:linux:linux_kernel:6.0:rc3::::::

References for CVE-2022-49958

URL	Tags
https://git.kernel.org/stable/c/0c6c522857151ac00150fd01baeebf231fb7d142	Patch
https://git.kernel.org/stable/c/44dfa645895a56f65461249deb5b81cd16560e2a	Patch
https://git.kernel.org/stable/c/a420d587260185407eda9c5766cfa9bdd5c39a56	Patch
https://git.kernel.org/stable/c/f612466ebecb12a00d9152344ddda6f6345f04dc	Patch

URL

CVE-2022-49958 | net/sched: fix netdevice reference leaks in attach_default_qdiscs()

Exploit prediction scoring system (EPSS) score for CVE-2022-49958

Common vulnerability scoring system (CVSS) metrics for CVE-2022-49958

Weakness enumeration for CVE-2022-49958

OS Trackers for CVE-2022-49958

Affected software / configurations for CVE-2022-49958

References for CVE-2022-49958