Linux Kernel TCP stack Use-After-Free Rated 7.8 CVSS

Last refreshed2026-10-15

Status: UPDATED | Advisory ID: CVE-2026-31580

Key Details

CVE	CVE-2026-31580
CVSS Score / Version	7.8 (High) / CVSS v3.1
Updated	2026-10-15
CVSS Vector	`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`
CVSS Prose	attack vector is local; attack complexity is low; privileges required is low; user interaction is none; scope is unchanged; confidentiality impact is high; integrity impact is high; availability impact is high.
Affected products	Linux Kernel and Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
Classified as	CWE-416 (Use After Free)
Exploitation prediction (EPSS)	0.18% probability of exploitation in the next 30 days (7% percentile) -- FIRST.org's EPSS model.

Affected Products, Subsystems & Sectors

Vendor	Product	Affected Versions	Patch Status
Linux	Linux Kernel
Siemens	SIMATIC S7-1500 TM MFP - GNU/Linux subsystem

Vendor

Product

Affected Versions

Patch Status

Linux

Linux Kernel

Siemens

SIMATIC S7-1500 TM MFP - GNU/Linux subsystem

Subsystems	Controllers & Field I/O, OT Supporting Infrastructure
Sectors	All Sectors

What to Know

In the Linux kernel, the following vulnerability has been resolved:

bcache: fix cached_dev.sb_bio use-after-free and crash

In our production environment, we have received multiple crash reports

regarding libceph, which have caught our attention:

```

[6888366.280350] Call Trace:

[6888366.280452] blk_update_request+0x14e/0x370

[6888366.280561] blk_mq_end_request+0x1a/0x130

[6888366.280671] rbd_img_handle_request+0x1a0/0x1b0 [rbd]

[6888366.280792] rbd_obj_handle_request+0x32/0x40 [rbd]

[6888366.280903] __complete_request+0x22/0x70 [libceph]

[6888366.281032] osd_dispatch+0x15e/0xb40 [libceph]

[6888366.281164] ? inet_recvmsg+0x5b/0xd0

[6888366.281272] ? ceph_tcp_recvmsg+0x6f/0xa0 [libceph]

[6888366.281405] ceph_con_process_message+0x79/0x140 [libceph]

[6888366.281534] ceph_con_v1_try_read+0x5d7/0xf30 [libceph]

[6888366.281661] ceph_con_workfn+0x329/0x680 [libceph]

```

After analyzing the coredump file, we found that the address of

dc->sb_bio has been freed. We know that cached_dev is only freed when it

is stopped.

Since sb_bio is a part of struct cached_dev, rather than an alloc every

time. If the device is stopped while writing to the superblock, the

released address will be accessed at endio.

This patch hopes to wait for sb_write to complete in cached_dev_free.

It should be noted that we analyzed the cause of the problem, then tell

all details to the QWEN and adopted the modifications it made. (NVD)

What to Do

Monitor Linux's and Siemens's web pages for any future patch releases.

References

Source	Reference
NVD	https://nvd.nist.gov/vuln/detail/CVE-2026-31580
CVE	https://www.cve.org/CVERecord?id=CVE-2026-31580

Source

Reference

NVD

https://nvd.nist.gov/vuln/detail/CVE-2026-31580

CVE

https://www.cve.org/CVERecord?id=CVE-2026-31580