s390/mm: Do not map lowcore with identity mapping
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 2 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-476.
Summary
In the Linux kernel, the following vulnerability has been resolved: s390/mm: Do not map lowcore with identity mapping Since the identity mapping is pinned to address zero the lowcore is always also mapped to address zero, this happens regardless of the relocate_lowcore command line option. If the option is specified the lowcore is mapped twice, instead of only once. This means that NULL pointer accesses will succeed instead of causing an exception (low address protection still applies, but covers only parts). To fix this never map the first two pages of physical memory with the identity mapping.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 6.10.11 to before 6.11 | 6.11 | Patch available | CNA |
| Linux | Linux | 6.11 and later | 6.12.44, 6.16.4, 6.17 | Patch available | CNA |
- Linux VendorLinux Affected 6.10.11 to before 6.11 Fixed in 6.11 Patch available CNA
- Linux VendorLinux Affected 6.11 and later Fixed in 6.12.44, 6.16.4, 6.17 Patch available CNA
CPE configurations NVD · 7
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 6.10.11 to before 6.11; 6.11.1 to before 6.12.44; 6.13 to before 6.16.4 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.11:-:*:*:*:*:*:* | 6.11 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.11:rc5:*:*:*:*:*:* | 6.11 rc5 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.11:rc6:*:*:*:*:*:* | 6.11 rc6 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.11:rc7:*:*:*:*:*:* | 6.11 rc7 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:* | 6.17 rc1 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:* | 6.17 rc2 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 6.10.11 to before 6.11; 6.11.1 to before 6.12.44; 6.13 to before 6.16.4 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.11:-:*:*:*:*:*:* Versions 6.11 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.11:rc5:*:*:*:*:*:* Versions 6.11 rc5 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.11:rc6:*:*:*:*:*:* Versions 6.11 rc6 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.11:rc7:*:*:*:*:*:* Versions 6.11 rc7 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:* Versions 6.17 rc1 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:* Versions 6.17 rc2 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.11
- Fix · CNA Linux (Linux) Fixed in 6.12.44, 6.16.4, 6.17
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Not affected: 3 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
Timeline
- 2026-10-02 Threatist record created from CVE-2025-38733
- 2026-10-03 Alias added: GHSA-9w66-p46h-j52f
- 2026-10-16 CISA SSVC decision points changed
References
More Linux Kernel vulnerabilities
- TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
- TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
- TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
- TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
- TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
Sources
- CVE-2025-38733 · CVE Program
- CVE-2025-38733 · NVD
- FIRST EPSS
- GHSA-9w66-p46h-j52f · GitHub Advisory Database · CC BY 4.0
- CVE-2025-38733 · Red Hat security data · CC BY 4.0
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