Vulnerability-Lookup

GHSA-J86X-F498-4JQP

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:

rds: tcp: unregister sysctl before tearing down listen socket

rds_tcp_exit_net() frees the per-netns RDS TCP listen socket via rds_tcp_kill_sock() before unregistering the per-netns sysctl table. Since rds_tcp_skbuf_handler() derives the netns from rtn->rds_tcp_listen_sock->sk, a concurrent sysctl write can race with netns teardown and dereference the freed socket/sk.

KASAN reports the race as:

BUG: KASAN: slab-use-after-free in rds_tcp_skbuf_handler+0x2aa/0x2e0 rds_tcp_skbuf_handler net/rds/tcp.c:721 proc_sys_call_handler fs/proc/proc_sysctl.c vfs_write fs/read_write.c __x64_sys_pwrite64 fs/read_write.c

Fix this by unregistering the RDS TCP sysctl table before calling rds_tcp_kill_sock(). unregister_net_sysctl_table() prevents new sysctl handlers from starting and waits for in-flight handlers to finish, so the listen socket can then be released safely. The fix was tested against the linked reproducer.

Severity

7.8 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-68290"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-10T13:20:18Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nrds: tcp: unregister sysctl before tearing down listen socket\n\nrds_tcp_exit_net() frees the per-netns RDS TCP listen socket via\nrds_tcp_kill_sock() before unregistering the per-netns sysctl table.  Since\nrds_tcp_skbuf_handler() derives the netns from\nrtn-\u003erds_tcp_listen_sock-\u003esk, a concurrent sysctl write can race with\nnetns teardown and dereference the freed socket/sk.\n\nKASAN reports the race as:\n\n  BUG: KASAN: slab-use-after-free in rds_tcp_skbuf_handler+0x2aa/0x2e0\n  rds_tcp_skbuf_handler              net/rds/tcp.c:721\n  proc_sys_call_handler              fs/proc/proc_sysctl.c\n  vfs_write                          fs/read_write.c\n  __x64_sys_pwrite64                 fs/read_write.c\n\nFix this by unregistering the RDS TCP sysctl table before calling\nrds_tcp_kill_sock().  unregister_net_sysctl_table() prevents new sysctl\nhandlers from starting and waits for in-flight handlers to finish, so\nthe listen socket can then be released safely. The fix was tested\nagainst the linked reproducer.",
  "id": "GHSA-j86x-f498-4jqp",
  "modified": "2026-08-14T00:31:54Z",
  "published": "2026-08-10T15:33:45Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-68290"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/167e54c703ccd4fa028feb568b0d1002020cff86"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/16df2d154ec82e2f7e7585b4fa154751ba37729a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3aa13fe0c1bb7bc5312f878e61523e5d8cf3f85d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/80fffed08dc1c10e971066941d2daa56253f1552"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-68290 (GCVE-0-2026-68290)

Vulnerability from cvelistv5 – Published: 2026-08-10 12:02 – Updated: 2026-08-17 05:02

Title

rds: tcp: unregister sysctl before tearing down listen socket

Summary

In the Linux kernel, the following vulnerability has been resolved: rds: tcp: unregister sysctl before tearing down listen socket rds_tcp_exit_net() frees the per-netns RDS TCP listen socket via rds_tcp_kill_sock() before unregistering the per-netns sysctl table. Since rds_tcp_skbuf_handler() derives the netns from rtn->rds_tcp_listen_sock->sk, a concurrent sysctl write can race with netns teardown and dereference the freed socket/sk. KASAN reports the race as: BUG: KASAN: slab-use-after-free in rds_tcp_skbuf_handler+0x2aa/0x2e0 rds_tcp_skbuf_handler net/rds/tcp.c:721 proc_sys_call_handler fs/proc/proc_sysctl.c vfs_write fs/read_write.c __x64_sys_pwrite64 fs/read_write.c Fix this by unregistering the RDS TCP sysctl table before calling rds_tcp_kill_sock(). unregister_net_sysctl_table() prevents new sysctl handlers from starting and waits for in-flight handlers to finish, so the listen socket can then be released safely. The fix was tested against the linked reproducer.

Severity

7.8 (High)


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

Assigner

Linux mitre root

References

4 references

URL	Tags
https://git.kernel.org/stable/c/80fffed08dc1c10e9…
https://git.kernel.org/stable/c/16df2d154ec82e2f7…
https://git.kernel.org/stable/c/3aa13fe0c1bb7bc53…
https://git.kernel.org/stable/c/167e54c703ccd4fa0…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: de8d6de0ee27be4b2b1e5b06f04aeacbabbba492 , < 80fffed08dc1c10e971066941d2daa56253f1552 (git) Affected: 7f5611cbc4871c7fb1ad36c2e5a9edad63dca95c , < 16df2d154ec82e2f7e7585b4fa154751ba37729a (git) Affected: 7f5611cbc4871c7fb1ad36c2e5a9edad63dca95c , < 3aa13fe0c1bb7bc5312f878e61523e5d8cf3f85d (git) Affected: 7f5611cbc4871c7fb1ad36c2e5a9edad63dca95c , < 167e54c703ccd4fa028feb568b0d1002020cff86 (git) Affected: 6.12.10 , < 6.12.101 (semver)
Linux	Linux	Affected: 6.13 Unaffected: 0 , < 6.13 (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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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
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          "programFiles": [
            "net/rds/tcp.c"
          ],
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              "versionType": "git"
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              "status": "affected",
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          "versions": [
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              "version": "6.13"
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              "versionType": "semver"
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              "versionType": "semver"
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              "status": "unaffected",
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              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.101",
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                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrds: tcp: unregister sysctl before tearing down listen socket\n\nrds_tcp_exit_net() frees the per-netns RDS TCP listen socket via\nrds_tcp_kill_sock() before unregistering the per-netns sysctl table.  Since\nrds_tcp_skbuf_handler() derives the netns from\nrtn-\u003erds_tcp_listen_sock-\u003esk, a concurrent sysctl write can race with\nnetns teardown and dereference the freed socket/sk.\n\nKASAN reports the race as:\n\n  BUG: KASAN: slab-use-after-free in rds_tcp_skbuf_handler+0x2aa/0x2e0\n  rds_tcp_skbuf_handler              net/rds/tcp.c:721\n  proc_sys_call_handler              fs/proc/proc_sysctl.c\n  vfs_write                          fs/read_write.c\n  __x64_sys_pwrite64                 fs/read_write.c\n\nFix this by unregistering the RDS TCP sysctl table before calling\nrds_tcp_kill_sock().  unregister_net_sysctl_table() prevents new sysctl\nhandlers from starting and waits for in-flight handlers to finish, so\nthe listen socket can then be released safely. The fix was tested\nagainst the linked reproducer."
        }
      ],
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            "baseSeverity": "HIGH",
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            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The vulnerability is triggered by a local write() /pwrite64() to the per-netns sysctl file /proc/sys/net/rds/tcp/rds_tcp_{snd,rcv}buf racing with network namespace teardown; no network traffic reaches the vulnerable handler, so local syscall access is required.\nAC:L - Although this is a race, the attacker controls both sides: they create the netns, keep the sysctl fd open, choose when the netns is destroyed, and issue the concurrent sysctl write in a tight loop, so the race can be retried indefinitely until won.\nPR:L - Only an unprivileged local account is needed: unshare -Urn yields CAP_NET_ADMIN over the new netns\u0027s user_ns, and net_ctl_permissions()/net_ctl_set_ownership() then grant that user write access to the RDS TCP sysctls, while the rds_tcp module is autoloaded by an unprivileged AF_RDS socket.\nUI:N - The attacker performs every step itself \u2014 namespace creation, opening the sysctl file, triggering teardown and writing \u2014 with no action required from any other user or administrator.\nS:U - The use-after-free occurs on kernel slab objects belonging to the same kernel security authority; there is no crossing of a VM, IOMMU or other security boundary.\nC:H - The handler reads the freed listen socket and then dereferences lsock-\u003esk and sock_net(sk); by spraying the freed socket/sk slabs the attacker can steer these dereferences to chosen addresses, turning the use-after-free read into a kernel memory disclosure primitive.\nI:H - Reallocating the freed struct socket/sk with attacker-controlled data lets the attacker supply a bogus struct net pointer that drives rds_tcp_sysctl_reset()/rds_conn_path_drop() over the global RDS connection list, corrupting kernel state and giving the usual UAF path toward control-flow hijack.\nA:H - The confirmed KASAN slab-use-after-free on the freed listen socket readily oopses or panics the kernel, and the race can be repeated by an unprivileged user until it hits, giving a reliable denial of service."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:02:25.806Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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        },
        {
          "url": "https://git.kernel.org/stable/c/3aa13fe0c1bb7bc5312f878e61523e5d8cf3f85d"
        },
        {
          "url": "https://git.kernel.org/stable/c/167e54c703ccd4fa028feb568b0d1002020cff86"
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      "title": "rds: tcp: unregister sysctl before tearing down listen socket",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-68290",
    "datePublished": "2026-08-10T12:02:23.425Z",
    "dateReserved": "2026-07-30T09:28:09.380Z",
    "dateUpdated": "2026-08-17T05:02:25.806Z",
    "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.

Action not permitted

GHSA-J86X-F498-4JQP

CVE-2026-68290 (GCVE-0-2026-68290)

Tags

Sightings

Nomenclature