CVE-2025-39939

linux: In the Linux kernel, the following vulnerability has been resolved: iommu/s390: Fix memory corruption when using ide...

CVE-2025-39939 is fixed in 12 products on 1 platform, first by DEBIAN-CVE-2025-39939, released October 4, 2025. It is not reported as exploited. Patch Radar priority: High.

High
CVSS
7.8
high
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0015
3rd percentile

In the Linux kernel, the following vulnerability has been resolved: iommu/s390: Fix memory corruption when using identity domain zpci_get_iommu_ctrs() returns counter information to be reported as part of device statistics; these counters are stored as part of the s390_domain. The problem, however, is that the identity domain is not backed by an s390_domain and so the conversion via to_s390_domain() yields a bad address that is zero'd initially and read on-demand later via a sysfs read. These counters aren't necessary for the identity domain; just return NULL in this case. This issue was discovered via KASAN with reports that look like: BUG: KASAN: global-out-of-bounds in zpci_fmb_enable_device when using the identity domain for a device on s390.

Where it's fixed

ProductFixed inFixReleased
Linux
kernel-64kb · sles 15.7 6.4.0-150700.53.81.1 SUSE-SU-2026:4254-1 Oct 7, 2026
kernel-azure · sles 15.7 6.4.0-150700.53.81.1 SUSE-SU-2026:4254-1 Oct 7, 2026
kernel-default · sles 15.7 6.4.0-150700.53.81.1 SUSE-SU-2026:4254-1 Oct 7, 2026
kernel-default-base · sles 15.7 6.4.0-150700.53.81.1.150700.17.45.1 SUSE-SU-2026:4254-1 Oct 7, 2026
kernel-docs · sles 15.7 6.4.0-150700.53.81.1 SUSE-SU-2026:4254-1 Oct 7, 2026
kernel-livepatch-SLE15-SP7-RT_Update_20 · sles 15.7 1-150700.1.3.1 SUSE-SU-2026:4120-1 Sep 10, 2026
kernel-livepatch-SLE15-SP7_Update_21 · sles 15.7 1-150700.15.3.1 SUSE-SU-2026:4254-1 Oct 7, 2026
kernel-obs-build · sles 15.7 6.4.0-150700.53.81.1 SUSE-SU-2026:4254-1 Oct 7, 2026
kernel-source · sles 15.7 6.4.0-150700.53.81.1 SUSE-SU-2026:4254-1 Oct 7, 2026
kernel-syms · sles 15.7 6.4.0-150700.53.81.1 SUSE-SU-2026:4254-1 Oct 7, 2026
kernel-zfcpdump · sles 15.7 6.4.0-150700.53.81.1 SUSE-SU-2026:4254-1 Oct 7, 2026
linux · Debian 14 6.16.9-1 DEBIAN-CVE-2025-39939 Oct 4, 2025

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