What’s Vulnerable › Vulnerabilities
CVE-2025-39694: s390/sclp: Fix SCCB present check
- Severity: medium (CVSS 5.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.2% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2025-09-05 · updated 2026-10-19
- Weakness: CWE-476
Description
In the Linux kernel, the following vulnerability has been resolved: s390/sclp: Fix SCCB present check Tracing code called by the SCLP interrupt handler contains early exits if the SCCB address associated with an interrupt is NULL. This check is performed after physical to virtual address translation. If the kernel identity mapping does not start at address zero, the resulting virtual address is never zero, so that the NULL checks won't work. Subsequently this may result in incorrect accesses to the first page of the identity mapping. Fix this by introducing a function that handles the NULL case before address translation.
Affected products
- Debian Linux: 11.0
- Linux kernel: from 5.16 before 6.1.149; from 6.2 before 6.6.103; from 6.7 before 6.12.44; from 6.13 before 6.16.4; 6.17-rc1, 6.17-rc2 — fixed in 6.1.149, 6.12.44, 6.16.4, 6.6.103
How to fix
Upgrade to a fixed version: Linux kernel 6.1.149, 6.12.44, 6.16.4, 6.6.103. Check the vendor advisory for mitigations.
References
- https://git.kernel.org/stable/c/430fa71027b6ac9bb0ce5532b8d0676777d4219a
- https://git.kernel.org/stable/c/61605c847599fbfdfafe638607841c7d73719081
- https://git.kernel.org/stable/c/86c2825791c3836a8f77a954b9c5ebe6fab410c5
- https://git.kernel.org/stable/c/aa5073ac1a2a274812f3b04c278992e68ff67cc7
- https://git.kernel.org/stable/c/bf83ae3537359af088d6577812ed93113dfbcb7b
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
- https://cert-portal.siemens.com/productcert/html/ssa-032379.html
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