CVE-2026-68140 (GCVE-0-2026-68140)

Vulnerability from cvelistv5 – Published: 2026-08-10 11:59 – Updated: 2026-08-19 16:29
VLAI
Title
net/iucv: fix use-after-free of a severed iucv_path
Summary
In the Linux kernel, the following vulnerability has been resolved: net/iucv: fix use-after-free of a severed iucv_path af_iucv queues not-yet-received message notifications on iucv->message_q, each holding a raw pointer to the connection's iucv_path. When the peer severs the connection, iucv_sever_path() frees that path with iucv_path_free() but leaves the notifications queued. A later recvmsg() drains message_q via iucv_process_message_q() and hands the stale path to message_receive() -- a use-after-free of the freed iucv_path. Drop the queued notifications when the path is severed; once the path is gone they can no longer be received. This also frees the notifications leaked when a socket is closed with messages still queued.
Severity
8.8 (High)
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: f0703c80e5156406ad947cb67fe277725b48080f , < 5f08c5e50bcb4680069bd3f9edd5728308816ded (git)
Affected: f0703c80e5156406ad947cb67fe277725b48080f , < c24faf11bd31bfe0500aca12cbdd5a573a954a5d (git)
Affected: f0703c80e5156406ad947cb67fe277725b48080f , < 99ddb33748698296a6f17b9b34aa3d16a406bb3c (git)
Affected: f0703c80e5156406ad947cb67fe277725b48080f , < 23658b350b4107e8292045c2044983fd426fa15d (git)
Affected: f0703c80e5156406ad947cb67fe277725b48080f , < a5bbaddf69853117f28173c3f5c8fc14c6b2ec82 (git)
Affected: f0703c80e5156406ad947cb67fe277725b48080f , < 900cd6d8119b7f3ae5c4bf82f922ff5957df43db (git)
Affected: f0703c80e5156406ad947cb67fe277725b48080f , < f579582c03ed526281a8450159baf1d35099a85f (git)
Affected: f0703c80e5156406ad947cb67fe277725b48080f , < be7cc4656eb1f54029610e82d1f0fdd3f9b5ec0a (git)
guessed Create a notification for this product.
Linux Linux Affected: 2.6.24
Unaffected: 0 , < 2.6.24 (semver)
Unaffected: 5.10.265 , ≤ 5.10.* (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)
guessed Create a notification for this product.
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/iucv: fix use-after-free of a severed iucv_path\n\naf_iucv queues not-yet-received message notifications on iucv-\u003emessage_q,\neach holding a raw pointer to the connection\u0027s iucv_path.  When the peer\nsevers the connection, iucv_sever_path() frees that path with\niucv_path_free() but leaves the notifications queued.  A later recvmsg()\ndrains message_q via iucv_process_message_q() and hands the stale path to\nmessage_receive() -- a use-after-free of the freed iucv_path.\n\nDrop the queued notifications when the path is severed; once the path is\ngone they can no longer be received.  This also frees the notifications\nleaked when a socket is closed with messages still queued."
        }
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            "version": "3.1"
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              "value": "AV:A - An adjacent z/VM guest or LPAR peer can establish an AF_IUCV connection and deliver IUCV message_pending and path_severed events to a victim; exploitation requires same-CPC IUCV reachability, not Internet-wide access.\nAC:L - The attacker deterministically floods IUCV messages to fill message_q, severs the connection to free iucv_path, then victim recvmsg() drains the stale queue; no uncontrollable timing or memory-layout luck is required.\nPR:N - On the victim, no local Linux account or capability is needed; any unauthorized adjacent IUCV peer that completes the AF_IUCV handshake can flood messages and sever the path against a listening service.\nUI:N - No special victim action is required beyond normal server recvmsg() on an established IUCV session; the attacker drives connection setup, message flood, and path sever entirely from the peer side.\nS:U - Impact is kernel memory corruption within the victim Linux guest; it does not cross hypervisor, VM-escape, or IOMMU security boundaries.\nC:H - Queued notifications dereference a freed struct iucv_path in message_receive(), passing stale pathid and private fields into CP IUCV RECEIVE calls\u2014a classic UAF enabling attacker-controlled heap reuse and kernel memory disclosure.\nI:H - Use-after-free of iucv_path lets an attacker reclaim the freed object and supply forged pathid and list pointers used by __iucv_message_receive(), providing heap corruption primitives suitable for arbitrary kernel write or code execution.\nA:H - Processing the stale path in iucv_process_message_q() dereferences freed kernel memory during message_receive(), reliably causing kernel oops or panic and total loss of availability even before full exploitation."
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        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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    "cveId": "CVE-2026-68140",
    "datePublished": "2026-08-10T11:59:03.761Z",
    "dateReserved": "2026-07-30T09:28:09.370Z",
    "dateUpdated": "2026-08-19T16:29:57.127Z",
    "state": "PUBLISHED"
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        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/iucv: fix use-after-free of a severed iucv_path\n\naf_iucv queues not-yet-received message notifications on iucv-\u003emessage_q,\neach holding a raw pointer to the connection\u0027s iucv_path.  When the peer\nsevers the connection, iucv_sever_path() frees that path with\niucv_path_free() but leaves the notifications queued.  A later recvmsg()\ndrains message_q via iucv_process_message_q() and hands the stale path to\nmessage_receive() -- a use-after-free of the freed iucv_path.\n\nDrop the queued notifications when the path is severed; once the path is\ngone they can no longer be received.  This also frees the notifications\nleaked when a socket is closed with messages still queued."
          }
        ],
        "id": "CVE-2026-68140",
        "lastModified": "2026-08-19T17:20:31.060",
        "metrics": {
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              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "ADJACENT_NETWORK",
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                "baseScore": 8.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
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              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
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        "published": "2026-08-10T13:19:59.650",
        "references": [
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            "url": "https://git.kernel.org/stable/c/23658b350b4107e8292045c2044983fd426fa15d"
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          },
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        "vulnStatus": "Received"
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    "redhat_vex": {
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      "current_release_date": "2026-08-31T11:13:27+00:00",
      "cve": "CVE-2026-68140",
      "id": "CVE-2026-68140",
      "initial_release_date": "2026-08-10T00:00:00+00:00",
      "product_status:known_affected": "261",
      "product_status:known_not_affected": "2",
      "product_status:under_investigation": "14",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: net/iucv: fix use-after-free of a severed iucv_path",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-68140.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-15T01:41:15Z",
      "cve": "CVE-2026-68140",
      "id": "CVE-2026-68140",
      "initial_release_date": "2026-08-18T16:56:15Z",
      "product_status:known_affected": "374",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-68140",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-68140.json",
      "version": "4"
    }
  }
}



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Tags
Taxonomy of the tags.





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

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.


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.