CVE-2026-68155 (GCVE-0-2026-68155)

Vulnerability from cvelistv5 – Published: 2026-08-10 11:59 – Updated: 2026-08-19 16:30
VLAI
Title
libceph: Reject monmaps advertising zero monitors
Summary
In the Linux kernel, the following vulnerability has been resolved: libceph: Reject monmaps advertising zero monitors A message of type CEPH_MSG_MON_MAP contains a monmap that is sent from a monitor to the client. This monmap contains information about the existing monitors in the cluster. Currently, a monmap indicating that there are zero monitors in the cluster is treated as valid. However, it is impossible to have zero monitors in the cluster and still receive a valid monmap from a monitor. Therefore, such a monmap must be corrupted and should be treated as invalid. Furthermore, a monmap with a monitor count of zero can subsequently crash the client when attempting to open a session with a monitor in __open_session(). This happens because the "BUG_ON(monc->monmap->num_mon < 1)" assertion in pick_new_mon() is triggered. This patch extends a check in ceph_monmap_decode() to also reject arriving mon_maps with num_mon == 0 rather than only with num_mon > CEPH_MAX_MON. [ idryomov: drop "log output for unusual values of num_mon" part ]
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: ba75bb98cfb93b62c54af25bf67ff90857264bbe , < caf082ef8609a6ac26159ce115f55ab7d00231a3 (git)
Affected: ba75bb98cfb93b62c54af25bf67ff90857264bbe , < e3ccd4ecab09b22f507f49cb7ed9990c7158ceab (git)
Affected: ba75bb98cfb93b62c54af25bf67ff90857264bbe , < 0591a15815b498be628a937146e44487d599ba33 (git)
Affected: ba75bb98cfb93b62c54af25bf67ff90857264bbe , < cd0d41bc569632eaaeccde9d2a6bc919ec00c407 (git)
Affected: ba75bb98cfb93b62c54af25bf67ff90857264bbe , < e67e8b694872c9bc66996040f9de9242f6236ed9 (git)
Affected: ba75bb98cfb93b62c54af25bf67ff90857264bbe , < 3b249546f59c3d6d3592c10657f82bc3f1faa07c (git)
Affected: ba75bb98cfb93b62c54af25bf67ff90857264bbe , < 40480eee361ed9676b3f844d532ac28b47251634 (git)
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Linux Linux Affected: 2.6.34
Unaffected: 0 , < 2.6.34 (semver)
Unaffected: 5.15.216 , ≤ 5.15.* (semver)
Unaffected: 6.1.183 , ≤ 6.1.* (semver)
Unaffected: 6.6.148 , ≤ 6.6.* (semver)
Unaffected: 6.12.101 , ≤ 6.12.* (semver)
Unaffected: 6.18.42 , ≤ 6.18.* (semver)
Unaffected: 7.1.6 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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          "product": "Linux",
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: Reject monmaps advertising zero monitors\n\nA message of type CEPH_MSG_MON_MAP contains a monmap that is sent from a\nmonitor to the client. This monmap contains information about the\nexisting monitors in the cluster. Currently, a monmap indicating that\nthere are zero monitors in the cluster is treated as valid. However, it\nis impossible to have zero monitors in the cluster and still receive a\nvalid monmap from a monitor. Therefore, such a monmap must be corrupted\nand should be treated as invalid. Furthermore, a monmap with a monitor\ncount of zero can subsequently crash the client when attempting to open\na session with a monitor in __open_session(). This happens because the\n\"BUG_ON(monc-\u003emonmap-\u003enum_mon \u003c 1)\" assertion in pick_new_mon() is\ntriggered.\n\nThis patch extends a check in ceph_monmap_decode() to also reject\narriving mon_maps with num_mon == 0 rather than only with\nnum_mon \u003e CEPH_MAX_MON.\n\n[ idryomov: drop \"log output for unusual values of num_mon\" part ]"
        }
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      "providerMetadata": {
        "dateUpdated": "2026-08-19T16:30:22.933Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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          "url": "https://git.kernel.org/stable/c/40480eee361ed9676b3f844d532ac28b47251634"
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    "cveId": "CVE-2026-68155",
    "datePublished": "2026-08-10T11:59:21.200Z",
    "dateReserved": "2026-07-30T09:28:09.371Z",
    "dateUpdated": "2026-08-19T16:30:22.933Z",
    "state": "PUBLISHED"
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Furthermore, a monmap with a monitor\\ncount of zero can subsequently crash the client when attempting to open\\na session with a monitor in __open_session(). This happens because the\\n\\\"BUG_ON(monc-\u003emonmap-\u003enum_mon \u003c 1)\\\" assertion in pick_new_mon() is\\ntriggered.\\n\\nThis patch extends a check in ceph_monmap_decode() to also reject\\narriving mon_maps with num_mon == 0 rather than only with\\nnum_mon \u003e CEPH_MAX_MON.\\n\\n[ idryomov: drop \\\"log output for unusual values of num_mon\\\" part ]\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"net/ceph/mon_client.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"ba75bb98cfb93b62c54af25bf67ff90857264bbe\",\"lessThan\":\"caf082ef8609a6ac26159ce115f55ab7d00231a3\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ba75bb98cfb93b62c54af25bf67ff90857264bbe\",\"lessThan\":\"e3ccd4ecab09b22f507f49cb7ed9990c7158ceab\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ba75bb98cfb93b62c54af25bf67ff90857264bbe\",\"lessThan\":\"0591a15815b498be628a937146e44487d599ba33\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ba75bb98cfb93b62c54af25bf67ff90857264bbe\",\"lessThan\":\"cd0d41bc569632eaaeccde9d2a6bc919ec00c407\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ba75bb98cfb93b62c54af25bf67ff90857264bbe\",\"lessThan\":\"e67e8b694872c9bc66996040f9de9242f6236ed9\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ba75bb98cfb93b62c54af25bf67ff90857264bbe\",\"lessThan\":\"3b249546f59c3d6d3592c10657f82bc3f1faa07c\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ba75bb98cfb93b62c54af25bf67ff90857264bbe\",\"lessThan\":\"40480eee361ed9676b3f844d532ac28b47251634\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"net/ceph/mon_client.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"2.6.34\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"2.6.34\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.15.216\",\"lessThanOrEqual\":\"5.15.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.183\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.148\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.101\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.42\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.6\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":7.5,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":3.6}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0591a15815b498be628a937146e44487d599ba33\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/3b249546f59c3d6d3592c10657f82bc3f1faa07c\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/40480eee361ed9676b3f844d532ac28b47251634\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/caf082ef8609a6ac26159ce115f55ab7d00231a3\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/cd0d41bc569632eaaeccde9d2a6bc919ec00c407\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/e3ccd4ecab09b22f507f49cb7ed9990c7158ceab\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/e67e8b694872c9bc66996040f9de9242f6236ed9\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-14T22:21:55+00:00",
      "cve": "CVE-2026-68155",
      "id": "CVE-2026-68155",
      "initial_release_date": "2026-08-10T11:59:21.200000+00:00",
      "product_status:known_affected": "260",
      "product_status:known_not_affected": "16",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: Linux kernel (libceph): Denial of Service due to malformed monitor maps",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-68155.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-08-18T00:08:30Z",
      "cve": "CVE-2026-68155",
      "id": "CVE-2026-68155",
      "initial_release_date": "2026-08-18T00:08:30Z",
      "product_status:known_affected": "99",
      "product_status:known_not_affected": "197",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-68155",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-68155.json",
      "version": "2"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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  • 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.
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  • 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.