# CVE-2025-39726: s390/ism: fix concurrency management in ism_cmd() CVE-2025-39726 is fixed in 24 products on 1 platform, first by DEBIAN-CVE-2025-39726, released September 5, 2025. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2025-39726 - Priority: Routine - CVSS: 5.5 (Moderate) - EPSS: 0.0025 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Sep 5, 2025 - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-39726 ## Description In the Linux kernel, the following vulnerability has been resolved: s390/ism: fix concurrency management in ism_cmd() The s390x ISM device data sheet clearly states that only one request-response sequence is allowable per ISM function at any point in time. Unfortunately as of today the s390/ism driver in Linux does not honor that requirement. This patch aims to rectify that. This problem was discovered based on Aliaksei's bug report which states that for certain workloads the ISM functions end up entering error state (with PEC 2 as seen from the logs) after a while and as a consequence connections handled by the respective function break, and for future connection requests the ISM device is not considered -- given it is in a dysfunctional state. During further debugging PEC 3A was observed as well. A kernel message like [ 1211.244319] zpci: 061a:00:00.0: Event 0x2 reports an error for PCI function 0x61a is a reliable indicator of the stated function entering error state with PEC 2. Let me also point out that a kernel message like [ 1211.244325] zpci: 061a:00:00.0: The ism driver bound to the device does not support error recovery is a reliable indicator that the ISM function won't be auto-recovered because the ISM driver currently lacks support for it. On a technical level, without this synchronization, commands (inputs to the FW) may be partially or fully overwritten (corrupted) by another CPU trying to issue commands on the same function. There is hard evidence that this can lead to DMB token values being used as DMB IOVAs, leading to PEC 2 PCI events indicating invalid DMA. But this is only one of the failure modes imaginable. In theory even completely losing one command and executing another one twice and then trying to interpret the outputs as if the command we intended to execute was actually executed and not the other one is also possible. Frankly, I don't feel confident about providing an exhaustive list of possible consequences. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | dtb-aarch64 opensuse-leap 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | dtb-aarch64 opensuse-leap 16.0 | 6.12.0-160000.6.1 | [OPENSUSE-SU-2025:20081-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20081-1.md) | Nov 25, 2025 | | Linux | kernel-64kb opensuse-leap 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-64kb opensuse-leap 16.0 | 6.12.0-160000.6.1 | [OPENSUSE-SU-2025:20081-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20081-1.md) | Nov 25, 2025 | | Linux | kernel-64kb sles 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-64kb sles 15.7 | 6.4.0-150700.53.22.1 | [SUSE-SU-2025:4057-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4057-1.md) | Nov 11, 2025 | | Linux | kernel-64kb sles 16.0 | 6.12.0-160000.6.1 | [SUSE-SU-2025:21139-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21139-1.md) | Nov 25, 2025 | | Linux | kernel-azure opensuse-leap 15.6 | 6.4.0-150600.8.52.1 | [SUSE-SU-2025:03634-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03634-1.md) | Oct 17, 2025 | | Linux | kernel-azure sles 15.6 | 6.4.0-150600.8.52.1 | [SUSE-SU-2025:03634-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03634-1.md) | Oct 17, 2025 | | Linux | kernel-azure sles 15.7 | 6.4.0-150700.20.18.1 | [SUSE-SU-2025:4132-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4132-1.md) | Nov 18, 2025 | | Linux | kernel-debug opensuse-leap 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-default opensuse-leap 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-default opensuse-leap 16.0 | 6.12.0-160000.6.1 | [OPENSUSE-SU-2025:20081-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20081-1.md) | Nov 25, 2025 | | Linux | kernel-default sles 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-default sles 15.7 | 6.4.0-150700.53.22.1 | [SUSE-SU-2025:4057-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4057-1.md) | Nov 11, 2025 | | Linux | kernel-default sles 16.0 | 6.12.0-160000.6.1 | [SUSE-SU-2025:21139-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21139-1.md) | Nov 25, 2025 | | Linux | kernel-default-base opensuse-leap 15.6 | 6.4.0-150600.23.73.1.150600.12.32.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-default-base opensuse-leap 16.0 | 6.12.0-160000.6.1.160000.2.4 | [OPENSUSE-SU-2025:20081-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20081-1.md) | Nov 25, 2025 | | Linux | kernel-default-base sles 15.6 | 6.4.0-150600.23.73.1.150600.12.32.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-default-base sles 15.7 | 6.4.0-150700.53.22.1.150700.17.15.1 | [SUSE-SU-2025:4057-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4057-1.md) | Nov 11, 2025 | | Linux | kernel-default-base sles 16.0 | 6.12.0-160000.6.1.160000.2.4 | [SUSE-SU-2025:21139-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21139-1.md) | Nov 25, 2025 | | Linux | kernel-docs opensuse-leap 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-docs opensuse-leap 16.0 | 6.12.0-160000.6.1 | [OPENSUSE-SU-2025:20081-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20081-1.md) | Nov 25, 2025 | | Linux | kernel-docs sles 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-docs sles 15.7 | 6.4.0-150700.53.22.1 | [SUSE-SU-2025:4057-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4057-1.md) | Nov 11, 2025 | | Linux | kernel-docs sles 16.0 | 6.12.0-160000.6.1 | [SUSE-SU-2025:21139-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21139-1.md) | Nov 25, 2025 | | Linux | kernel-kvmsmall opensuse-leap 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-kvmsmall opensuse-leap 16.0 | 6.12.0-160000.6.1 | [OPENSUSE-SU-2025:20081-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20081-1.md) | Nov 25, 2025 | | Linux | kernel-kvmsmall sles 16.0 | 6.12.0-160000.6.1 | [SUSE-SU-2025:21139-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21139-1.md) | Nov 25, 2025 | | Linux | kernel-livepatch-SLE15-SP6-RT_Update_16 sles 15.6 | 1-150600.1.3.1 | [SUSE-SU-2025:3751-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-3751-1.md) | Oct 23, 2025 | | Linux | kernel-livepatch-SLE15-SP6_Update_16 sles 15.6 | 1-150600.13.3.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-livepatch-SLE15-SP7-RT_Update_6 sles 15.7 | 1-150700.1.3.1 | [SUSE-SU-2025:4141-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4141-1.md) | Nov 19, 2025 | | Linux | kernel-livepatch-SLE15-SP7_Update_6 sles 15.7 | 1-150700.15.3.1 | [SUSE-SU-2025:4057-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4057-1.md) | Nov 11, 2025 | | Linux | kernel-obs-build opensuse-leap 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-obs-build opensuse-leap 16.0 | 6.12.0-160000.6.1 | [OPENSUSE-SU-2025:20081-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20081-1.md) | Nov 25, 2025 | | Linux | kernel-obs-build sles 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-obs-build sles 15.7 | 6.4.0-150700.53.22.1 | [SUSE-SU-2025:4057-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4057-1.md) | Nov 11, 2025 | | Linux | kernel-obs-qa opensuse-leap 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-obs-qa opensuse-leap 16.0 | 6.12.0-160000.6.1 | [OPENSUSE-SU-2025:20081-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20081-1.md) | Nov 25, 2025 | | Linux | kernel-obs-qa sles 16.0 | 6.12.0-160000.6.1 | [SUSE-SU-2025:21139-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21139-1.md) | Nov 25, 2025 | | Linux | kernel-rt opensuse-leap 15.6 | 6.4.0-150600.10.55.1 | [SUSE-SU-2025:3751-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-3751-1.md) | Oct 23, 2025 | | Linux | kernel-rt opensuse-leap 16.0 | 6.12.0-160000.6.1 | [OPENSUSE-SU-2025:20081-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20081-1.md) | Nov 25, 2025 | | Linux | kernel-rt_debug opensuse-leap 15.6 | 6.4.0-150600.10.55.1 | [SUSE-SU-2025:3751-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-3751-1.md) | Oct 23, 2025 | | Linux | kernel-source opensuse-leap 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-source opensuse-leap 16.0 | 6.12.0-160000.6.1 | [OPENSUSE-SU-2025:20081-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20081-1.md) | Nov 25, 2025 | | Linux | kernel-source sles 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-source sles 15.7 | 6.4.0-150700.53.22.1 | [SUSE-SU-2025:4057-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4057-1.md) | Nov 11, 2025 | | Linux | kernel-source sles 16.0 | 6.12.0-160000.6.1 | [SUSE-SU-2025:21139-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21139-1.md) | Nov 25, 2025 | | Linux | kernel-source-azure opensuse-leap 15.6 | 6.4.0-150600.8.52.1 | [SUSE-SU-2025:03634-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03634-1.md) | Oct 17, 2025 | | Linux | kernel-source-azure sles 15.6 | 6.4.0-150600.8.52.1 | [SUSE-SU-2025:03634-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03634-1.md) | Oct 17, 2025 | | Linux | kernel-source-azure sles 15.7 | 6.4.0-150700.20.18.1 | [SUSE-SU-2025:4132-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4132-1.md) | Nov 18, 2025 | | Linux | kernel-source-rt opensuse-leap 15.6 | 6.4.0-150600.10.55.1 | [SUSE-SU-2025:3751-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-3751-1.md) | Oct 23, 2025 | | Linux | kernel-syms opensuse-leap 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-syms opensuse-leap 16.0 | 6.12.0-160000.6.1 | [OPENSUSE-SU-2025:20081-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20081-1.md) | Nov 25, 2025 | | Linux | kernel-syms sles 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-syms sles 15.7 | 6.4.0-150700.53.22.1 | [SUSE-SU-2025:4057-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4057-1.md) | Nov 11, 2025 | | Linux | kernel-syms sles 16.0 | 6.12.0-160000.6.1 | [SUSE-SU-2025:21139-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21139-1.md) | Nov 25, 2025 | | Linux | kernel-syms-azure opensuse-leap 15.6 | 6.4.0-150600.8.52.1 | [SUSE-SU-2025:03634-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03634-1.md) | Oct 17, 2025 | | Linux | kernel-syms-azure sles 15.6 | 6.4.0-150600.8.52.1 | [SUSE-SU-2025:03634-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03634-1.md) | Oct 17, 2025 | | Linux | kernel-syms-azure sles 15.7 | 6.4.0-150700.20.18.1 | [SUSE-SU-2025:4132-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4132-1.md) | Nov 18, 2025 | | Linux | kernel-syms-rt opensuse-leap 15.6 | 6.4.0-150600.10.55.1 | [SUSE-SU-2025:3751-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-3751-1.md) | Oct 23, 2025 | | Linux | kernel-zfcpdump opensuse-leap 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-zfcpdump opensuse-leap 16.0 | 6.12.0-160000.6.1 | [OPENSUSE-SU-2025:20081-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20081-1.md) | Nov 25, 2025 | | Linux | kernel-zfcpdump sles 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-zfcpdump sles 15.7 | 6.4.0-150700.53.22.1 | [SUSE-SU-2025:4057-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4057-1.md) | Nov 11, 2025 | | Linux | kernel-zfcpdump sles 16.0 | 6.12.0-160000.6.1 | [SUSE-SU-2025:21139-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21139-1.md) | Nov 25, 2025 | | Linux | linux Debian 13.5 (trixie) | 6.12.41-1 | [DEBIAN-CVE-2025-39726](https://patchblox.com/security/data/fix/linux/debian-cve-2025-39726.md) | Sep 5, 2025 | | Linux | linux Debian 14 | 6.16.3-1 | [DEBIAN-CVE-2025-39726](https://patchblox.com/security/data/fix/linux/debian-cve-2025-39726.md) | Sep 5, 2025 | --- Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.