Vulnerability-Lookup

OESA-2025-2661 (CVE-2025-38415)

Vulnerability from osv_openeuler – Published: 2025-11-14 11:09 – Updated: 2026-08-06 11:09 – Source website

Summary

kernel security update

Details

The Linux Kernel, the operating system core itself.

Security Fix(es):

In the Linux kernel, the following vulnerability has been resolved:

Squashfs: check return result of sb_min_blocksize

Syzkaller reports an "UBSAN: shift-out-of-bounds in squashfs_bio_read" bug.

Syzkaller forks multiple processes which after mounting the Squashfs filesystem, issues an ioctl("/dev/loop0", LOOP_SET_BLOCK_SIZE, 0x8000). Now if this ioctl occurs at the same time another process is in the process of mounting a Squashfs filesystem on /dev/loop0, the failure occurs. When this happens the following code in squashfs_fill_super() fails.

msblk->devblksize = sb_min_blocksize(sb, SQUASHFS_DEVBLK_SIZE); msblk->devblksize_log2 = ffz(~msblk->devblksize);

sb_min_blocksize() returns 0, which means msblk->devblksize is set to 0.

As a result, ffz(~msblk->devblksize) returns 64, and msblk->devblksize_log2 is set to 64.

This subsequently causes the

UBSAN: shift-out-of-bounds in fs/squashfs/block.c:195:36 shift exponent 64 is too large for 64-bit type 'u64' (aka 'unsigned long long')

This commit adds a check for a 0 return by sb_min_blocksize().(CVE-2025-38415)

Severity

3.9 (Low)


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

References

URL

Type

	https://www.openeuler.org/zh/security/security-bu…	ADVISORY
	https://nvd.nist.gov/vuln/detail/CVE-2025-38415	ADVISORY

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "aarch64": [
          "bpftool-5.10.0-289.0.0.192.oe2203sp4.aarch64.rpm",
          "bpftool-debuginfo-5.10.0-289.0.0.192.oe2203sp4.aarch64.rpm",
          "kernel-5.10.0-289.0.0.192.oe2203sp4.aarch64.rpm",
          "kernel-debuginfo-5.10.0-289.0.0.192.oe2203sp4.aarch64.rpm",
          "kernel-debugsource-5.10.0-289.0.0.192.oe2203sp4.aarch64.rpm",
          "kernel-devel-5.10.0-289.0.0.192.oe2203sp4.aarch64.rpm",
          "kernel-headers-5.10.0-289.0.0.192.oe2203sp4.aarch64.rpm",
          "kernel-source-5.10.0-289.0.0.192.oe2203sp4.aarch64.rpm",
          "kernel-tools-5.10.0-289.0.0.192.oe2203sp4.aarch64.rpm",
          "kernel-tools-debuginfo-5.10.0-289.0.0.192.oe2203sp4.aarch64.rpm",
          "kernel-tools-devel-5.10.0-289.0.0.192.oe2203sp4.aarch64.rpm",
          "perf-5.10.0-289.0.0.192.oe2203sp4.aarch64.rpm",
          "perf-debuginfo-5.10.0-289.0.0.192.oe2203sp4.aarch64.rpm",
          "python3-perf-5.10.0-289.0.0.192.oe2203sp4.aarch64.rpm",
          "python3-perf-debuginfo-5.10.0-289.0.0.192.oe2203sp4.aarch64.rpm"
        ],
        "src": [
          "kernel-5.10.0-289.0.0.192.oe2203sp4.src.rpm"
        ],
        "x86_64": [
          "bpftool-5.10.0-289.0.0.192.oe2203sp4.x86_64.rpm",
          "bpftool-debuginfo-5.10.0-289.0.0.192.oe2203sp4.x86_64.rpm",
          "kernel-5.10.0-289.0.0.192.oe2203sp4.x86_64.rpm",
          "kernel-debuginfo-5.10.0-289.0.0.192.oe2203sp4.x86_64.rpm",
          "kernel-debugsource-5.10.0-289.0.0.192.oe2203sp4.x86_64.rpm",
          "kernel-devel-5.10.0-289.0.0.192.oe2203sp4.x86_64.rpm",
          "kernel-headers-5.10.0-289.0.0.192.oe2203sp4.x86_64.rpm",
          "kernel-source-5.10.0-289.0.0.192.oe2203sp4.x86_64.rpm",
          "kernel-tools-5.10.0-289.0.0.192.oe2203sp4.x86_64.rpm",
          "kernel-tools-debuginfo-5.10.0-289.0.0.192.oe2203sp4.x86_64.rpm",
          "kernel-tools-devel-5.10.0-289.0.0.192.oe2203sp4.x86_64.rpm",
          "perf-5.10.0-289.0.0.192.oe2203sp4.x86_64.rpm",
          "perf-debuginfo-5.10.0-289.0.0.192.oe2203sp4.x86_64.rpm",
          "python3-perf-5.10.0-289.0.0.192.oe2203sp4.x86_64.rpm",
          "python3-perf-debuginfo-5.10.0-289.0.0.192.oe2203sp4.x86_64.rpm"
        ]
      },
      "package": {
        "ecosystem": "openEuler:22.03-LTS-SP4",
        "name": "kernel",
        "purl": "pkg:rpm/openEuler/kernel\u0026distro=openEuler-22.03-LTS-SP4"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "5.10.0-289.0.0.192.oe2203sp4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "severity": "Low"
  },
  "details": "The Linux Kernel, the operating system core itself.\r\n\r\nSecurity Fix(es):\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nSquashfs: check return result of sb_min_blocksize\n\nSyzkaller reports an \u0026quot;UBSAN: shift-out-of-bounds in squashfs_bio_read\u0026quot; bug.\n\nSyzkaller forks multiple processes which after mounting the Squashfs\nfilesystem, issues an ioctl(\u0026quot;/dev/loop0\u0026quot;, LOOP_SET_BLOCK_SIZE, 0x8000). \nNow if this ioctl occurs at the same time another process is in the\nprocess of mounting a Squashfs filesystem on /dev/loop0, the failure\noccurs.  When this happens the following code in squashfs_fill_super()\nfails.\n\n----\nmsblk-\u0026gt;devblksize = sb_min_blocksize(sb, SQUASHFS_DEVBLK_SIZE);\nmsblk-\u0026gt;devblksize_log2 = ffz(~msblk-\u0026gt;devblksize);\n----\n\nsb_min_blocksize() returns 0, which means msblk-\u0026gt;devblksize is set to 0.\n\nAs a result, ffz(~msblk-\u0026gt;devblksize) returns 64, and msblk-\u0026gt;devblksize_log2\nis set to 64.\n\nThis subsequently causes the\n\nUBSAN: shift-out-of-bounds in fs/squashfs/block.c:195:36\nshift exponent 64 is too large for 64-bit type \u0026apos;u64\u0026apos; (aka\n\u0026apos;unsigned long long\u0026apos;)\n\nThis commit adds a check for a 0 return by sb_min_blocksize().(CVE-2025-38415)",
  "id": "OESA-2025-2661",
  "modified": "2026-08-06T11:09:47Z",
  "published": "2025-11-14T11:09:47Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2025-2661"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-38415"
    }
  ],
  "schema_version": "1.7.2",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "kernel security update",
  "upstream": [
    "CVE-2025-38415"
  ]
}

CVE-2025-38415 (GCVE-0-2025-38415)

Vulnerability from cvelistv5 – Published: 2025-07-25 13:32 – Updated: 2026-06-18 20:55

Title

Squashfs: check return result of sb_min_blocksize

Summary

In the Linux kernel, the following vulnerability has been resolved: Squashfs: check return result of sb_min_blocksize Syzkaller reports an "UBSAN: shift-out-of-bounds in squashfs_bio_read" bug. Syzkaller forks multiple processes which after mounting the Squashfs filesystem, issues an ioctl("/dev/loop0", LOOP_SET_BLOCK_SIZE, 0x8000). Now if this ioctl occurs at the same time another process is in the process of mounting a Squashfs filesystem on /dev/loop0, the failure occurs. When this happens the following code in squashfs_fill_super() fails. ---- msblk->devblksize = sb_min_blocksize(sb, SQUASHFS_DEVBLK_SIZE); msblk->devblksize_log2 = ffz(~msblk->devblksize); ---- sb_min_blocksize() returns 0, which means msblk->devblksize is set to 0. As a result, ffz(~msblk->devblksize) returns 64, and msblk->devblksize_log2 is set to 64. This subsequently causes the UBSAN: shift-out-of-bounds in fs/squashfs/block.c:195:36 shift exponent 64 is too large for 64-bit type 'u64' (aka 'unsigned long long') This commit adds a check for a 0 return by sb_min_blocksize().

Severity

No CVSS data available.

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-06-18 20:55 UTC

Assigner

Linux mitre root

References

10 references

URL	Tags
https://git.kernel.org/stable/c/db7096ea160e40d78…
https://git.kernel.org/stable/c/549f9e3d7b60d5380…
https://git.kernel.org/stable/c/5c51aa862cbeed2f3…
https://git.kernel.org/stable/c/6abf6b78c6fb112ee…
https://git.kernel.org/stable/c/4f99357dadbf9c979…
https://git.kernel.org/stable/c/0aff95d9bc7fb5400…
https://git.kernel.org/stable/c/295ab18c2dbce8d0a…
https://git.kernel.org/stable/c/734aa85390ea693bb…
https://lists.debian.org/debian-lts-announce/2025…
https://lists.debian.org/debian-lts-announce/2025…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 0aa666190509ffab81c202c5095a166be23961ac , < db7096ea160e40d78c67fce52e7cc51bde049497 (git) Affected: 0aa666190509ffab81c202c5095a166be23961ac , < 549f9e3d7b60d53808c98b9fde49b4f46d0524a5 (git) Affected: 0aa666190509ffab81c202c5095a166be23961ac , < 5c51aa862cbeed2f3887f0382a2708956710bd68 (git) Affected: 0aa666190509ffab81c202c5095a166be23961ac , < 6abf6b78c6fb112eee495f5636ffcc350dd2ce25 (git) Affected: 0aa666190509ffab81c202c5095a166be23961ac , < 4f99357dadbf9c979ad737156ad4c37fadf7c56b (git) Affected: 0aa666190509ffab81c202c5095a166be23961ac , < 0aff95d9bc7fb5400ca8af507429c4b067bdb425 (git) Affected: 0aa666190509ffab81c202c5095a166be23961ac , < 295ab18c2dbce8d0ac6ecf7c5187e16e1ac8b282 (git) Affected: 0aa666190509ffab81c202c5095a166be23961ac , < 734aa85390ea693bb7eaf2240623d41b03705c84 (git)
Linux	Linux	Affected: 2.6.29 Unaffected: 0 , < 2.6.29 (semver) Unaffected: 5.4.295 , ≤ 5.4.* (semver) Unaffected: 5.10.239 , ≤ 5.10.* (semver) Unaffected: 5.15.186 , ≤ 5.15.* (semver) Unaffected: 6.1.142 , ≤ 6.1.* (semver) Unaffected: 6.6.94 , ≤ 6.6.* (semver) Unaffected: 6.12.34 , ≤ 6.12.* (semver) Unaffected: 6.15.3 , ≤ 6.15.* (semver) Unaffected: 6.16 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2025-11-03T17:37:45.927Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
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            "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"
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            "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html"
          }
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        "title": "CVE Program Container"
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              "content": {
                "id": "CVE-2025-38415",
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                    "Technical Impact": "partial"
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                "role": "CISA Coordinator",
                "timestamp": "2026-06-18T20:55:21.631432Z",
                "version": "2.0.3"
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      "descriptions": [
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nSquashfs: check return result of sb_min_blocksize\n\nSyzkaller reports an \"UBSAN: shift-out-of-bounds in squashfs_bio_read\" bug.\n\nSyzkaller forks multiple processes which after mounting the Squashfs\nfilesystem, issues an ioctl(\"/dev/loop0\", LOOP_SET_BLOCK_SIZE, 0x8000). \nNow if this ioctl occurs at the same time another process is in the\nprocess of mounting a Squashfs filesystem on /dev/loop0, the failure\noccurs.  When this happens the following code in squashfs_fill_super()\nfails.\n\n----\nmsblk-\u003edevblksize = sb_min_blocksize(sb, SQUASHFS_DEVBLK_SIZE);\nmsblk-\u003edevblksize_log2 = ffz(~msblk-\u003edevblksize);\n----\n\nsb_min_blocksize() returns 0, which means msblk-\u003edevblksize is set to 0.\n\nAs a result, ffz(~msblk-\u003edevblksize) returns 64, and msblk-\u003edevblksize_log2\nis set to 64.\n\nThis subsequently causes the\n\nUBSAN: shift-out-of-bounds in fs/squashfs/block.c:195:36\nshift exponent 64 is too large for 64-bit type \u0027u64\u0027 (aka\n\u0027unsigned long long\u0027)\n\nThis commit adds a check for a 0 return by sb_min_blocksize()."
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          "url": "https://git.kernel.org/stable/c/734aa85390ea693bb7eaf2240623d41b03705c84"
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    "datePublished": "2025-07-25T13:32:09.711Z",
    "dateReserved": "2025-04-16T04:51:24.013Z",
    "dateUpdated": "2026-06-18T20:55:27.614Z",
    "state": "PUBLISHED"
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  "dataVersion": "5.2"
}

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.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.