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GHSA-83X9-86WR-8VH2

Vulnerability from github – Published: 2026-08-10 15:33 – Updated: 2026-08-14 00:31

Details

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

libceph: bound pg_{temp,upmap,upmap_items} length to CEPH_PG_MAX_SIZE

__decode_pg_temp() decodes an user-controlled length but only rejects values large enough to overflow the allocation; it does not bound it to CEPH_PG_MAX_SIZE. The helper backs both pg_temp and pg_upmap decoding, and apply_upmap()/get_temp_osds() later copy the decoded list into the fixed-size on-stack array struct ceph_osds.osds[CEPH_PG_MAX_SIZE]. A monitor that sends an OSDMap with a pg_temp/pg_upmap entry longer than 32 thus causes a stack out-of-bounds write.

An OSD set for a single PG can never exceed CEPH_PG_MAX_SIZE, so reject longer entries at decode time. The bound is well below the old overflow threshold, so it also covers the allocation-size overflow the previous check guarded against.

BUG: KASAN: stack-out-of-bounds in ceph_pg_to_up_acting_osds Write of size 4 ... by task exploit kasan_report (mm/kasan/report.c:595) ceph_pg_to_up_acting_osds (net/ceph/osdmap.c:2617 net/ceph/osdmap.c:2833) calc_target (net/ceph/osd_client.c:1638) __submit_request (net/ceph/osd_client.c:2394) ceph_osdc_start_request (net/ceph/osd_client.c:2490) ceph_osdc_call (net/ceph/osd_client.c:5164) rbd_dev_image_probe (drivers/block/rbd.c:6899) do_rbd_add (drivers/block/rbd.c:7138) ... kernel BUG at net/ceph/osdmap.c:2670!

[ idryomov: do the same in __decode_pg_upmap_items() ]

Severity

9.8 (Critical)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-68159"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-10T13:20:02Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: bound pg_{temp,upmap,upmap_items} length to CEPH_PG_MAX_SIZE\n\n__decode_pg_temp() decodes an user-controlled length but only rejects\nvalues large enough to overflow the allocation; it does not bound it to\nCEPH_PG_MAX_SIZE. The helper backs both pg_temp and pg_upmap decoding, and\napply_upmap()/get_temp_osds() later copy the decoded list into the fixed-size\non-stack array struct ceph_osds.osds[CEPH_PG_MAX_SIZE]. A monitor that sends\nan OSDMap with a pg_temp/pg_upmap entry longer than 32 thus causes a stack\nout-of-bounds write.\n\nAn OSD set for a single PG can never exceed CEPH_PG_MAX_SIZE, so reject longer\nentries at decode time. The bound is well below the old overflow threshold, so\nit also covers the allocation-size overflow the previous check guarded against.\n\n  BUG: KASAN: stack-out-of-bounds in ceph_pg_to_up_acting_osds\n  Write of size 4 ... by task exploit\n   kasan_report (mm/kasan/report.c:595)\n   ceph_pg_to_up_acting_osds (net/ceph/osdmap.c:2617 net/ceph/osdmap.c:2833)\n   calc_target (net/ceph/osd_client.c:1638)\n   __submit_request (net/ceph/osd_client.c:2394)\n   ceph_osdc_start_request (net/ceph/osd_client.c:2490)\n   ceph_osdc_call (net/ceph/osd_client.c:5164)\n   rbd_dev_image_probe (drivers/block/rbd.c:6899)\n   do_rbd_add (drivers/block/rbd.c:7138)\n   ...\n  kernel BUG at net/ceph/osdmap.c:2670!\n\n[ idryomov: do the same in __decode_pg_upmap_items() ]",
  "id": "GHSA-83x9-86wr-8vh2",
  "modified": "2026-08-14T00:31:52Z",
  "published": "2026-08-10T15:33:38Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-68159"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9f00f9cf2be293efe899db67dc5272e3a9c62717"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e36663145abd7024f0281dfb22fdef65f185845b"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-68159 (GCVE-0-2026-68159)

Vulnerability from cvelistv5 – Published: 2026-08-10 11:59 – Updated: 2026-08-17 04:59

Title

libceph: bound pg_{temp,upmap,upmap_items} length to CEPH_PG_MAX_SIZE

Summary

In the Linux kernel, the following vulnerability has been resolved: libceph: bound pg_{temp,upmap,upmap_items} length to CEPH_PG_MAX_SIZE __decode_pg_temp() decodes an user-controlled length but only rejects values large enough to overflow the allocation; it does not bound it to CEPH_PG_MAX_SIZE. The helper backs both pg_temp and pg_upmap decoding, and apply_upmap()/get_temp_osds() later copy the decoded list into the fixed-size on-stack array struct ceph_osds.osds[CEPH_PG_MAX_SIZE]. A monitor that sends an OSDMap with a pg_temp/pg_upmap entry longer than 32 thus causes a stack out-of-bounds write. An OSD set for a single PG can never exceed CEPH_PG_MAX_SIZE, so reject longer entries at decode time. The bound is well below the old overflow threshold, so it also covers the allocation-size overflow the previous check guarded against. BUG: KASAN: stack-out-of-bounds in ceph_pg_to_up_acting_osds Write of size 4 ... by task exploit kasan_report (mm/kasan/report.c:595) ceph_pg_to_up_acting_osds (net/ceph/osdmap.c:2617 net/ceph/osdmap.c:2833) calc_target (net/ceph/osd_client.c:1638) __submit_request (net/ceph/osd_client.c:2394) ceph_osdc_start_request (net/ceph/osd_client.c:2490) ceph_osdc_call (net/ceph/osd_client.c:5164) rbd_dev_image_probe (drivers/block/rbd.c:6899) do_rbd_add (drivers/block/rbd.c:7138) ... kernel BUG at net/ceph/osdmap.c:2670! [ idryomov: do the same in __decode_pg_upmap_items() ]

Severity

9.8 (Critical)


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

Assigner

Linux mitre root

References

2 references

URL	Tags
https://git.kernel.org/stable/c/e36663145abd7024f…
https://git.kernel.org/stable/c/9f00f9cf2be293efe…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: a303bb0e58345fe9f7ab2f82b90266f2b5036058 , < e36663145abd7024f0281dfb22fdef65f185845b (git) Affected: a303bb0e58345fe9f7ab2f82b90266f2b5036058 , < 9f00f9cf2be293efe899db67dc5272e3a9c62717 (git)
Linux	Linux	Affected: 4.13 Unaffected: 0 , < 4.13 (semver) Unaffected: 7.1.6 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ceph/osdmap.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "e36663145abd7024f0281dfb22fdef65f185845b",
              "status": "affected",
              "version": "a303bb0e58345fe9f7ab2f82b90266f2b5036058",
              "versionType": "git"
            },
            {
              "lessThan": "9f00f9cf2be293efe899db67dc5272e3a9c62717",
              "status": "affected",
              "version": "a303bb0e58345fe9f7ab2f82b90266f2b5036058",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/ceph/osdmap.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.13"
            },
            {
              "lessThan": "4.13",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.6",
                  "versionStartIncluding": "4.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "4.13",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: bound pg_{temp,upmap,upmap_items} length to CEPH_PG_MAX_SIZE\n\n__decode_pg_temp() decodes an user-controlled length but only rejects\nvalues large enough to overflow the allocation; it does not bound it to\nCEPH_PG_MAX_SIZE. The helper backs both pg_temp and pg_upmap decoding, and\napply_upmap()/get_temp_osds() later copy the decoded list into the fixed-size\non-stack array struct ceph_osds.osds[CEPH_PG_MAX_SIZE]. A monitor that sends\nan OSDMap with a pg_temp/pg_upmap entry longer than 32 thus causes a stack\nout-of-bounds write.\n\nAn OSD set for a single PG can never exceed CEPH_PG_MAX_SIZE, so reject longer\nentries at decode time. The bound is well below the old overflow threshold, so\nit also covers the allocation-size overflow the previous check guarded against.\n\n  BUG: KASAN: stack-out-of-bounds in ceph_pg_to_up_acting_osds\n  Write of size 4 ... by task exploit\n   kasan_report (mm/kasan/report.c:595)\n   ceph_pg_to_up_acting_osds (net/ceph/osdmap.c:2617 net/ceph/osdmap.c:2833)\n   calc_target (net/ceph/osd_client.c:1638)\n   __submit_request (net/ceph/osd_client.c:2394)\n   ceph_osdc_start_request (net/ceph/osd_client.c:2490)\n   ceph_osdc_call (net/ceph/osd_client.c:5164)\n   rbd_dev_image_probe (drivers/block/rbd.c:6899)\n   do_rbd_add (drivers/block/rbd.c:7138)\n   ...\n  kernel BUG at net/ceph/osdmap.c:2670!\n\n[ idryomov: do the same in __decode_pg_upmap_items() ]"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - Malicious pg_temp/pg_upmap data arrives in CEPH_MSG_OSD_MAP from a Ceph monitor or OSD over TCP, is decoded in libceph, and later triggers stack corruption in ceph_pg_to_up_acting_osds during RBD/CephFS/libceph client I/O.\nAC:L - A compromised or attacker-controlled monitor can publish osdmap entries with length \u003e32 for chosen PGs; once the client subscribes, kernel I/O paths such as RBD mount/probe via calc_target deterministically invoke apply_upmap/get_temp_osds and overflow the stack buffer.\nPR:N - Exploitation requires no privileges on the victim host; any machine acting as a Ceph client that receives a forged osdmap from a cluster peer over the network can be attacked without local user capabilities or namespace tricks.\nUI:N - No victim user action is needed during exploitation beyond the host already being a Ceph client; forged osdmaps are applied automatically and the overflow fires on subsequent kernel client operations without interactive steps.\nS:U - Impact is confined to kernel memory on the Ceph client host (privilege escalation or crash); it does not cross VM, IOMMU, or sandbox boundaries to other security authorities.\nC:H - KASAN-confirmed stack out-of-bounds write in ceph_pg_to_up_acting_osds corrupts adjacent stack memory and can be leveraged for arbitrary kernel memory disclosure, not merely a bounded leak.\nI:H - Unbounded copy loops in apply_upmap() and get_temp_osds() write attacker-controlled u32 OSD IDs past the fixed osds[CEPH_PG_MAX_SIZE] stack array, enabling control-flow hijack and arbitrary kernel writes.\nA:H - The reported reproducer triggers KASAN stack-out-of-bounds followed by kernel BUG in ceph_pg_to_up_acting_osds, demonstrating a reliable kernel oops or panic from malformed osdmap processing on Ceph clients."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T04:59:55.290Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/e36663145abd7024f0281dfb22fdef65f185845b"
        },
        {
          "url": "https://git.kernel.org/stable/c/9f00f9cf2be293efe899db67dc5272e3a9c62717"
        }
      ],
      "title": "libceph: bound pg_{temp,upmap,upmap_items} length to CEPH_PG_MAX_SIZE",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-68159",
    "datePublished": "2026-08-10T11:59:25.697Z",
    "dateReserved": "2026-07-30T09:28:09.371Z",
    "dateUpdated": "2026-08-17T04:59:55.290Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "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.

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GHSA-83X9-86WR-8VH2

CVE-2026-68159 (GCVE-0-2026-68159)

Tags

Sightings

Nomenclature