Vulnerability-Lookup

GHSA-9478-77XP-CR7G

Vulnerability from github – Published: 2026-09-11 21:31 – Updated: 2026-09-14 15:32

Details

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

libceph: validate OSD extent maps before cursor advance

net/ceph/osd_client.c:osd_sparse_read() validates that the sparse-read data length matches the summed extent lengths, but it does not validate that each OSD-supplied extent is monotonic and lies inside the original request range. A malformed authenticated OSD reply can advertise a far-forward nonzero extent offset with a matching data length and make the client advance the message-data cursor beyond the request buffer. This reaches the BUG_ON(!*length) assertion in ceph_msg_data_next() from the client receive path.

Impact: A malicious or compromised authenticated Ceph OSD peer can crash a kernel Ceph client via a malformed sparse-read reply.

Reject sparse extent maps that overflow, move backwards, overlap, or extend outside the original sparse-read request before advancing the cursor.

[ idryomov: perform sparse_extent_map_valid() check a bit earlier, in CEPH_SPARSE_READ_DATA_LEN instead of CEPH_SPARSE_READ_DATA_PRE state ]

Severity

7.5 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-89657"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-11T20:19:51Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: validate OSD extent maps before cursor advance\n\nnet/ceph/osd_client.c:osd_sparse_read() validates that the sparse-read\ndata length matches the summed extent lengths, but it does not validate\nthat each OSD-supplied extent is monotonic and lies inside the original\nrequest range. A malformed authenticated OSD reply can advertise a\nfar-forward nonzero extent offset with a matching data length and make\nthe client advance the message-data cursor beyond the request buffer.\nThis reaches the BUG_ON(!*length) assertion in ceph_msg_data_next() from\nthe client receive path.\n\nImpact: A malicious or compromised authenticated Ceph OSD peer can crash\na kernel Ceph client via a malformed sparse-read reply.\n\nReject sparse extent maps that overflow, move backwards, overlap, or\nextend outside the original sparse-read request before advancing the\ncursor.\n\n[ idryomov: perform sparse_extent_map_valid() check a bit earlier,\n  in CEPH_SPARSE_READ_DATA_LEN instead of CEPH_SPARSE_READ_DATA_PRE\n  state ]",
  "id": "GHSA-9478-77xp-cr7g",
  "modified": "2026-09-14T15:32:33Z",
  "published": "2026-09-11T21:31:35Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89657"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/058ffa81f9440c5b4714685611cf697fd3739ec9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/201db408872ca12cf09e36bf0f560138c3dcfa1c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2571b35883268a266554e80d368e67fdfea7fb9d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/94ae5145c520618802b0a24c047dcd5f05835db8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9ec08b7499a62c6d4afa93d36ab47a43fcad57d1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-89657 (GCVE-0-2026-89657)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:45 – Updated: 2026-09-14 12:01

Title

libceph: validate OSD extent maps before cursor advance

Summary

In the Linux kernel, the following vulnerability has been resolved: libceph: validate OSD extent maps before cursor advance net/ceph/osd_client.c:osd_sparse_read() validates that the sparse-read data length matches the summed extent lengths, but it does not validate that each OSD-supplied extent is monotonic and lies inside the original request range. A malformed authenticated OSD reply can advertise a far-forward nonzero extent offset with a matching data length and make the client advance the message-data cursor beyond the request buffer. This reaches the BUG_ON(!*length) assertion in ceph_msg_data_next() from the client receive path. Impact: A malicious or compromised authenticated Ceph OSD peer can crash a kernel Ceph client via a malformed sparse-read reply. Reject sparse extent maps that overflow, move backwards, overlap, or extend outside the original sparse-read request before advancing the cursor. [ idryomov: perform sparse_extent_map_valid() check a bit earlier, in CEPH_SPARSE_READ_DATA_LEN instead of CEPH_SPARSE_READ_DATA_PRE state ]

Severity

7.5 (High)


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

Assigner

Linux mitre root

References

5 references

URL	Tags
https://git.kernel.org/stable/c/94ae5145c52061880…
https://git.kernel.org/stable/c/058ffa81f9440c5b4…
https://git.kernel.org/stable/c/2571b35883268a266…
https://git.kernel.org/stable/c/201db408872ca12cf…
https://git.kernel.org/stable/c/9ec08b7499a62c6d4…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: f628d799972799023d32c2542bb2639eb8c4f84e , < 94ae5145c520618802b0a24c047dcd5f05835db8 (git) Affected: f628d799972799023d32c2542bb2639eb8c4f84e , < 058ffa81f9440c5b4714685611cf697fd3739ec9 (git) Affected: f628d799972799023d32c2542bb2639eb8c4f84e , < 2571b35883268a266554e80d368e67fdfea7fb9d (git) Affected: f628d799972799023d32c2542bb2639eb8c4f84e , < 201db408872ca12cf09e36bf0f560138c3dcfa1c (git) Affected: f628d799972799023d32c2542bb2639eb8c4f84e , < 9ec08b7499a62c6d4afa93d36ab47a43fcad57d1 (git)
Linux	Linux	Affected: 6.6 Unaffected: 0 , < 6.6 (semver) Unaffected: 6.6.157 , ≤ 6.6.* (semver) Unaffected: 6.12.109 , ≤ 6.12.* (semver) Unaffected: 6.18.50 , ≤ 6.18.* (semver) Unaffected: 7.2.4 , ≤ 7.2.* (semver) Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)

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      "affected": [
        {
          "defaultStatus": "unaffected",
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          "programFiles": [
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              "versionType": "semver"
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        }
      ],
      "cpeApplicability": [
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          "nodes": [
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              "cpeMatch": [
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: validate OSD extent maps before cursor advance\n\nnet/ceph/osd_client.c:osd_sparse_read() validates that the sparse-read\ndata length matches the summed extent lengths, but it does not validate\nthat each OSD-supplied extent is monotonic and lies inside the original\nrequest range. A malformed authenticated OSD reply can advertise a\nfar-forward nonzero extent offset with a matching data length and make\nthe client advance the message-data cursor beyond the request buffer.\nThis reaches the BUG_ON(!*length) assertion in ceph_msg_data_next() from\nthe client receive path.\n\nImpact: A malicious or compromised authenticated Ceph OSD peer can crash\na kernel Ceph client via a malformed sparse-read reply.\n\nReject sparse extent maps that overflow, move backwards, overlap, or\nextend outside the original sparse-read request before advancing the\ncursor.\n\n[ idryomov: perform sparse_extent_map_valid() check a bit earlier,\n  in CEPH_SPARSE_READ_DATA_LEN instead of CEPH_SPARSE_READ_DATA_PRE\n  state ]"
        }
      ],
      "metrics": [
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              "value": "AV:N - The malformed sparse-read extent map is consumed in osd_sparse_read() on the Ceph messenger TCP receive path (messenger_v1/v2) when a kernel CephFS client handles an MOSDOpReply from a remote OSD; no local syscall or ioctl is required to parse the reply.\nAC:L - A malicious OSD fully controls the sparse extent offsets and lengths and can advertise a far-forward nonzero extent with a matching data length, deterministically advancing the message-data cursor past the request buffer into BUG_ON(!*length) in ceph_msg_data_next() with no race or special memory layout.\nPR:N - The attacker acts as a remote Ceph OSD peer on a compromised or attacker-controlled cluster and needs no account, capabilities, or user-namespace privileges on the victim Linux host; any kernel CephFS client connected to that cluster is exposed.\nUI:N - Once CephFS is mounted with fscrypt-encrypted files or the sparseread option, netfs/buffered reads and encrypted RMW writes issue CEPH_OSD_OP_SPARSE_READ as normal I/O; the OSD can crash the client on the next such reply without further victim action at exploit time.\nS:U - The BUG_ON panic occurs in the kernel Ceph client\u0027s receive path on the same host and does not cross a VM, IOMMU, or sandbox boundary to another security authority.\nC:N - ceph_msg_data_next() hits BUG_ON(!*length) and related cursor assertions when the buffer is exhausted, before any out-of-bounds page access; there is no use-after-free, OOB read, or other information-disclosure primitive.\nI:N - Cursor over-advance is stopped by BUG_ON assertions rather than writing past the allocated request pages; hole-zeroing via zero_user_segment stays inside the destination buffer until the panic, so there is no arbitrary kernel write or control-flow hijack.\nA:H - BUG_ON(!*length) in ceph_msg_data_next() on the client receive path causes a kernel oops or panic, fully denying availability of the affected Ceph client host until reboot."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-14T12:01:51.323Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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        },
        {
          "url": "https://git.kernel.org/stable/c/9ec08b7499a62c6d4afa93d36ab47a43fcad57d1"
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      ],
      "title": "libceph: validate OSD extent maps before cursor advance",
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    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89657",
    "datePublished": "2026-09-11T19:45:46.118Z",
    "dateReserved": "2026-09-11T19:38:34.743Z",
    "dateUpdated": "2026-09-14T12:01:51.323Z",
    "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.

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

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