CVE-2017-12190

Severity: medium (CVSS 6.5 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2017-11-22 · updated 2026-06-17
Weakness: CWE-400

Description

The bio_map_user_iov and bio_unmap_user functions in block/bio.c in the Linux kernel before 4.13.8 do unbalanced refcounting when a SCSI I/O vector has small consecutive buffers belonging to the same page. The bio_add_pc_page function merges them into one, but the page reference is never dropped. This causes a memory leak and possible system lockup (exploitable against the host OS by a guest OS user, if a SCSI disk is passed through to a virtual machine) due to an out-of-memory condition.

Affected products

Linux kernel: through 4.13.7

References

http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=2b04e8f6bbb196cab4b232af0f8d48ff2c7a8058
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=95d78c28b5a85bacbc29b8dba7c04babb9b0d467
http://seclists.org/oss-sec/2017/q4/52
http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.13.8
http://www.securityfocus.com/bid/101911
https://access.redhat.com/errata/RHSA-2018:0654
https://access.redhat.com/errata/RHSA-2018:0676
https://access.redhat.com/errata/RHSA-2018:1062
https://access.redhat.com/errata/RHSA-2018:1854
https://access.redhat.com/errata/RHSA-2019:1170
https://access.redhat.com/errata/RHSA-2019:1190
https://bugzilla.redhat.com/show_bug.cgi?id=1495089

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