Vulnerability-Lookup

GHSA-PM9C-RRJM-4V2F

Vulnerability from github – Published: 2025-10-04 09:30 – Updated: 2026-01-27 21:31

Details

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.

Severity

7.8 (High)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2025-39939"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-787"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-10-04T08:15:46Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\niommu/s390: Fix memory corruption when using identity domain\n\nzpci_get_iommu_ctrs() returns counter information to be reported as part\nof device statistics; these counters are stored as part of the s390_domain.\nThe problem, however, is that the identity domain is not backed by an\ns390_domain and so the conversion via to_s390_domain() yields a bad address\nthat is zero\u0027d initially and read on-demand later via a sysfs read.\nThese counters aren\u0027t necessary for the identity domain; just return NULL\nin this case.\n\nThis issue was discovered via KASAN with reports that look like:\nBUG: KASAN: global-out-of-bounds in zpci_fmb_enable_device\nwhen using the identity domain for a device on s390.",
  "id": "GHSA-pm9c-rrjm-4v2f",
  "modified": "2026-01-27T21:31:35Z",
  "published": "2025-10-04T09:30:21Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-39939"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/17a58caf3863163c4a84a218a9649be2c8061443"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b3506e9bcc777ed6af2ab631c86a9990ed97b474"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2025-39939 (GCVE-0-2025-39939)

Vulnerability from cvelistv5 – Published: 2025-10-04 07:31 – Updated: 2026-10-15 22:02

Title

iommu/s390: Fix memory corruption when using identity domain

Summary

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.

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-15 21:54 UTC

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 6639 records in the last 180 days details

References

2 references

URL	Tags
https://git.kernel.org/stable/c/17a58caf3863163c4…
https://git.kernel.org/stable/c/b3506e9bcc777ed6a…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 64af12c6ec3afd7d44bc8b2044eee59f98059087 , < 17a58caf3863163c4a84a218a9649be2c8061443 (git) Affected: 64af12c6ec3afd7d44bc8b2044eee59f98059087 , < b3506e9bcc777ed6af2ab631c86a9990ed97b474 (git)
Linux	Linux	Affected: 6.15 Unaffected: 0 , < 6.15 (semver) Unaffected: 6.16.9 , ≤ 6.16.* (semver) Unaffected: 6.17 , ≤ * (original_commit_for_fix)

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                "id": "CVE-2025-39939",
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                  },
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                    "Technical Impact": "total"
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                "role": "CISA Coordinator",
                "timestamp": "2026-10-15T21:54:54.159629Z",
                "version": "2.0.3"
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          "shortName": "CISA-ADP"
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              "status": "affected",
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              "versionType": "git"
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              "version": "0",
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              "version": "6.16.9",
              "versionType": "semver"
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              "negate": false,
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\niommu/s390: Fix memory corruption when using identity domain\n\nzpci_get_iommu_ctrs() returns counter information to be reported as part\nof device statistics; these counters are stored as part of the s390_domain.\nThe problem, however, is that the identity domain is not backed by an\ns390_domain and so the conversion via to_s390_domain() yields a bad address\nthat is zero\u0027d initially and read on-demand later via a sysfs read.\nThese counters aren\u0027t necessary for the identity domain; just return NULL\nin this case.\n\nThis issue was discovered via KASAN with reports that look like:\nBUG: KASAN: global-out-of-bounds in zpci_fmb_enable_device\nwhen using the identity domain for a device on s390."
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              "value": "AV:L - The vulnerable code is s390 PCI/IOMMU infrastructure reached through local interfaces only \u2014 `pci_enable_device()` on driver bind and the debugfs `/sys/kernel/debug/pci/\u003cdev\u003e/statistics` file. There is no network-facing path to `zpci_get_iommu_ctrs()`.\nAC:L - Once a device uses the identity domain, the out-of-bounds access is fully deterministic \u2014 no race to win and no attacker-uninfluenceable memory layout \u2014 corrupting the same fixed 40-byte region on every `zpci_fmb_enable_device()` call and leaking it on every statistics read. Passthrough mode is a supported, documented runtime option on s390, not an obscure debug-only Kconfig.\nPR:L - The corrupting write happens automatically during normal `pci_enable_device()` at boot/driver bind with no attacker action at all, and the disclosure file is created world-readable (`S_IFREG | S_IRUGO | S_IWUSR`), so an unprivileged local user on a system with a traversable debugfs can harvest the leaked kernel global memory. No capability check gates `zpci_get_iommu_ctrs()` itself.\nUI:N - No victim action is needed; the counter reset fires on device enable and the OOB read happens on a plain file read. Nothing requires a second user to mount, open, or configure anything.\nS:U - The corruption and disclosure are confined to kernel `.data` within the kernel\u0027s own security authority \u2014 the bug mislocates statistics counters and does not alter IOMMU translation or bypass the DMA isolation boundary. Standard kernel-internal memory corruption is Unchanged scope.\nC:H - `pci_sw_counter_show()` reads 40 bytes past the end of `s390_identity_domain` and prints them verbatim to userspace, disclosing adjacent kernel global data such as `blocking_domain`\u0027s `ops`/`owner` function-pointer and structure pointers \u2014 a direct kernel address leak defeating KASLR and exposing kernel state.\nI:H - Five `atomic64_set()` calls zero 40 bytes of adjacent kernel global memory, overwriting live control structures \u2014 at +16 past the object this lands exactly on an `iommu_domain`\u0027s `const struct iommu_domain_ops *ops` field, nulling a function-pointer table. This is genuine kernel memory corruption of security-relevant control data, as the commit subject states.\nA:H - Zeroing adjacent globals (e.g. `blocking_domain.ops`) produces NULL-pointer dereferences in `__iommu_attach_device()` when the blocking/release domain is later attached, and KASAN reports a `global-out-of-bounds` BUG in `zpci_fmb_enable_device`. Both result in a kernel oops/panic."
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    "dateReserved": "2025-04-16T07:20:57.148Z",
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    "state": "PUBLISHED"
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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

Order JSON

How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

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