Answer in brief
CVE-2025-39726 records a Critical severity (CVSS 9.8) vulnerability in s390/ism: fix concurrency management in ism_cmd(). The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 9.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.16:rc1:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.16:rc2:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.16:rc3:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.16:rc4:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.16:rc5:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.16:rc6:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.16:rc7:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=684b89bc39ce4f204b1a2b180f39f2eb36a6b695 <faf44487dfc80817f178dc8de7a0b73f960d019b || >=684b89bc39ce4f204b1a2b180f39f2eb36a6b695 <1194ad0d44d66b273a02a3a22882dc863a68d764 || >=684b89bc39ce4f204b1a2b180f39f2eb36a6b695 <fafaa4982bedb5532f5952000f714a3e63023f40 || >=684b89bc39ce4f204b1a2b180f39f2eb36a6b695 <897e8601b9cff1d054cdd53047f568b0e1995726 | faf44487dfc80817f178dc8de7a0b73f960d019b, 1194ad0d44d66b273a02a3a22882dc863a68d764, fafaa4982bedb5532f5952000f714a3e63023f40, 897e8601b9cff1d054cdd53047f568b0e1995726 |
| Linux/Linuxgeneric | 4.19 | Not reported |
| Linux/Linuxgeneric | >=684b89bc39ce4f204b1a2b180f39f2eb36a6b695 <79536c83cf38c285709757c4026da4ae151223ae || >=684b89bc39ce4f204b1a2b180f39f2eb36a6b695 <faf44487dfc80817f178dc8de7a0b73f960d019b || >=684b89bc39ce4f204b1a2b180f39f2eb36a6b695 <1194ad0d44d66b273a02a3a22882dc863a68d764 || >=684b89bc39ce4f204b1a2b180f39f2eb36a6b695 <fafaa4982bedb5532f5952000f714a3e63023f40 || >=684b89bc39ce4f204b1a2b180f39f2eb36a6b695 <897e8601b9cff1d054cdd53047f568b0e1995726 | 79536c83cf38c285709757c4026da4ae151223ae, faf44487dfc80817f178dc8de7a0b73f960d019b, 1194ad0d44d66b273a02a3a22882dc863a68d764, fafaa4982bedb5532f5952000f714a3e63023f40, 897e8601b9cff1d054cdd53047f568b0e1995726 |
Published upstream
Sep 5, 2025
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 30, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
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.
Quoted source text, attributed separately from HOL analysis.