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CVE-2026-68335

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: rds: drop incoming messages that cross network namespace boundaries rds_find_bound() looks up the destination socket using a global rhashtable keyed solely on (addr, port, scope_id). Network namespaces are not part of the key, so a sender in netns A can deliver an incoming message (inc) to a socket that lives in a different netns B. When this happens, inc->i_conn points to an rds_connection whose c_net is netns A, but the receiving rs lives in netns B. Once the child process that created netns A exits, cleanup_net() calls rds_loop_exit_net() -> rds_loop_kill_conns() -> rds_conn_destroy(), freeing that connection. If the survivor socket in netns B still holds the inc, any subsequent dereference of inc->i_conn is a use-after-free. There are two dangerous sites in rds_clear_recv_queue(): 1. inc->i_conn->c_lcong (offset 88 of freed rds_connection, size 200) read via rds_recv_rcvbuf_delta() -- confirmed by KASAN. 2. inc->i_conn->c_trans->inc_free(inc) (function pointer at offset 80) called via rds_inc_put() when the inc refcount reaches zero -- same race window, potential call-through-freed-object primitive. The bug is reachable from unprivileged user namespaces (CLONE_NEWUSER + CLONE_NEWNET), available since Linux 3.8. Fix this by rejecting the delivery in rds_recv_incoming() when the socket returned by rds_find_bound() belongs to a different network namespace than the connection that carried the message. Use the existing rds_conn_net() / sock_net() helpers and net_eq() for the comparison.

Severity
HIGH
CVSS score
7.8 (v3.1)
Vulnerability status
Received
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-08-10 13:20:23.863000
Last modified
2026-10-19 22:17:13.720000
View original CVE JSON 
{
  "id": "CVE-2026-68335",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-08-10T13:20:23.863",
  "lastModified": "2026-10-19T22:17:13.720",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrds: drop incoming messages that cross network namespace boundaries\n\nrds_find_bound() looks up the destination socket using a global\nrhashtable keyed solely on (addr, port, scope_id).  Network namespaces\nare not part of the key, so a sender in netns A can deliver an incoming\nmessage (inc) to a socket that lives in a different netns B.\n\nWhen this happens, inc->i_conn points to an rds_connection whose c_net\nis netns A, but the receiving rs lives in netns B.  Once the child\nprocess that created netns A exits, cleanup_net() calls\nrds_loop_exit_net() -> rds_loop_kill_conns() -> rds_conn_destroy(),\nfreeing that connection.  If the survivor socket in netns B still holds\nthe inc, any subsequent dereference of inc->i_conn is a use-after-free.\n\nThere are two dangerous sites in rds_clear_recv_queue():\n  1. inc->i_conn->c_lcong (offset 88 of freed rds_connection, size 200)\n     read via rds_recv_rcvbuf_delta() -- confirmed by KASAN.\n  2. inc->i_conn->c_trans->inc_free(inc) (function pointer at offset 80)\n     called via rds_inc_put() when the inc refcount reaches zero -- same\n     race window, potential call-through-freed-object primitive.\n\nThe bug is reachable from unprivileged user namespaces\n(CLONE_NEWUSER + CLONE_NEWNET), available since Linux 3.8.\n\nFix this by rejecting the delivery in rds_recv_incoming() when the\nsocket returned by rds_find_bound() belongs to a different network\nnamespace than the connection that carried the message.  Use the\nexisting rds_conn_net() / sock_net() helpers and net_eq() for the\ncomparison."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "net/rds/recv.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "c809195f5523dd4d09403bbb1c9732d548aa0d1e",
              "lessThan": "742ff6f02545212e991cd8b45011e40d2c2ef25a",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "c809195f5523dd4d09403bbb1c9732d548aa0d1e",
              "lessThan": "abff41fd928328bbf3dda1140beb2e61fa424ccd",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "c809195f5523dd4d09403bbb1c9732d548aa0d1e",
              "lessThan": "03c574112e5d066df0ddce36d7438e850bcf3050",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "c809195f5523dd4d09403bbb1c9732d548aa0d1e",
              "lessThan": "1e2e2d9806944fe485824d617c8b7c78116c22db",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "c809195f5523dd4d09403bbb1c9732d548aa0d1e",
              "lessThan": "cfb3ce07b705e486e022a2f2b1242b48f13981ff",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "c809195f5523dd4d09403bbb1c9732d548aa0d1e",
              "lessThan": "9591042533140dfe6608d9344806d567dcd39d02",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "c809195f5523dd4d09403bbb1c9732d548aa0d1e",
              "lessThan": "0f8690e3869109cd5803ccb400889d20a0b54e0e",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "c809195f5523dd4d09403bbb1c9732d548aa0d1e",
              "lessThan": "5521ae71e32a8069ed4ca6e792179dc57bc43ab2",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "c827073c95fde388bc65fe5227f944eaf859b9f0",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "4.17.19",
              "lessThan": "4.18",
              "versionType": "semver",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "net/rds/recv.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "4.18",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "4.18",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "5.10.265",
              "lessThanOrEqual": "5.10.*",
              "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:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-10-16T15:47:14.247347Z",
          "id": "CVE-2026-68335",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-416"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/03c574112e5d066df0ddce36d7438e850bcf3050",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/0f8690e3869109cd5803ccb400889d20a0b54e0e",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/1e2e2d9806944fe485824d617c8b7c78116c22db",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/5521ae71e32a8069ed4ca6e792179dc57bc43ab2",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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    {
      "url": "https://git.kernel.org/stable/c/742ff6f02545212e991cd8b45011e40d2c2ef25a",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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    {
      "url": "https://git.kernel.org/stable/c/9591042533140dfe6608d9344806d567dcd39d02",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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    {
      "url": "https://git.kernel.org/stable/c/abff41fd928328bbf3dda1140beb2e61fa424ccd",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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    {
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}