CVE-2026-72220 (GCVE-0-2026-72220)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:54 – Updated: 2026-08-17 05:41
VLAI
Title
sunrpc: harden rq_procinfo lifecycle to prevent double-free
Summary
In the Linux kernel, the following vulnerability has been resolved: sunrpc: harden rq_procinfo lifecycle to prevent double-free The svc_release_rqst() function executes the callback inside rqstp->rq_procinfo->pc_release. However, if a worker thread begins processing a new request and encounters an early error path (e.g., unsupported protocol, short frame, or bad auth) before a valid rq_procinfo is installed, a stale release hook can be re-triggered against reused state from the previous RPC, resulting in a double-free or use-after-free vulnerability. Harden the lifecycle of rq_procinfo by: 1. Ensuring svc_release_rqst() always clears rq_procinfo after the optional pc_release() call, regardless of whether the hook exists. 2. Explicitly clearing rq_procinfo at request entry in svc_process() before any early decode or drop paths. 3. Ensuring svc_process_bc() does the same at backchannel entry. This guarantees that error flows will not encounter a non-NULL stale rq_procinfo pointer when there is nothing to release.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/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: d9adbb6e10bf7d4223d3d521ede1b2052903bc5e , < 66014ab165cb01bfef5836939412a8ef98d5d5ff (git)
Affected: d9adbb6e10bf7d4223d3d521ede1b2052903bc5e , < 31ba490c02d476a5e4f90b8845932ac9db8aa71b (git)
Affected: d9adbb6e10bf7d4223d3d521ede1b2052903bc5e , < 18d216788bef06332ff8901670ecf1ed8f6eb614 (git)
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Linux Linux Affected: 6.18
Unaffected: 0 , < 6.18 (semver)
Unaffected: 6.18.40 , ≤ 6.18.* (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
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          "product": "Linux",
          "programFiles": [
            "net/sunrpc/svc.c"
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsunrpc: harden rq_procinfo lifecycle to prevent double-free\n\nThe svc_release_rqst() function executes the callback inside\nrqstp-\u003erq_procinfo-\u003epc_release. However, if a worker thread begins\nprocessing a new request and encounters an early error path (e.g.,\nunsupported protocol, short frame, or bad auth) before a valid\nrq_procinfo is installed, a stale release hook can be re-triggered\nagainst reused state from the previous RPC, resulting in a double-free\nor use-after-free vulnerability.\n\nHarden the lifecycle of rq_procinfo by:\n1. Ensuring svc_release_rqst() always clears rq_procinfo after the\n   optional pc_release() call, regardless of whether the hook exists.\n2. Explicitly clearing rq_procinfo at request entry in svc_process()\n   before any early decode or drop paths.\n3. Ensuring svc_process_bc() does the same at backchannel entry.\n\nThis guarantees that error flows will not encounter a non-NULL stale\nrq_procinfo pointer when there is nothing to release."
        }
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              "lang": "en",
              "value": "AV:N - The flaw is in server-side SUNRPC request handling reached from remote RPC over TCP/UDP/RDMA transports used by nfsd and lockd (svc_recv\u2192svc_handle_xprt\u2192svc_process), exploitable by sending crafted ONC/RPC packets to listening NFS/NLM ports.\nAC:L - An attacker controls the RPC sequence and timing (valid request then malformed/short/bad-auth/bad-prog packet on the same pooled worker) to reliably re-trigger a stale pc_release without depending on uncontrollable layout or victim state.\nPR:N - Trigger paths include pre-authentication failures (garbage credentials, unknown program/version, short frames) that still call svc_release_rqst; stale rq_procinfo can be left by any prior RPC on the same worker, so no attacker credentials are required.\nUI:N - Exploitation requires only network RPC traffic to an already-running NFS/NLM server; no end-user actions such as mounting a share or opening files are needed beyond normal server exposure.\nS:U - Impact is kernel heap corruption and privilege escalation within the host kernel context; it does not inherently cross a VM, container, or IOMMU security boundary to another authority.\nC:H - The bug is an explicit double-free/use-after-free of per-request NFS release state (e.g. nfsd4_release_compoundargs kfree/vfree chains and fh_put paths), enabling arbitrary kernel memory disclosure when exploited.\nI:H - Re-invoking pc_release on reused svc_rqst buffers corrupts heap metadata and object lifetimes, providing a standard kernel double-free/UAF primitive suitable for arbitrary write and code execution.\nA:H - Repeated or mistimed pc_release calls can immediately panic the kernel via SLUB double-free detection, oops, or wedged nfsd worker threads, causing complete loss of availability on NFS-serving systems."
            }
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        "dateUpdated": "2026-08-17T05:41:41.598Z",
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        "shortName": "Linux"
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    "cveId": "CVE-2026-72220",
    "datePublished": "2026-08-15T05:54:13.800Z",
    "dateReserved": "2026-08-09T03:40:39.913Z",
    "dateUpdated": "2026-08-17T05:41:41.598Z",
    "state": "PUBLISHED"
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    "redhat_vex": {
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      "current_release_date": "2026-08-17T13:36:53+00:00",
      "cve": "CVE-2026-72220",
      "id": "CVE-2026-72220",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_affected": "76",
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      "product_status:under_investigation": "14",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: sunrpc: harden rq_procinfo lifecycle to prevent double-free",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72220.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-08-21T00:42:22Z",
      "cve": "CVE-2026-72220",
      "id": "CVE-2026-72220",
      "initial_release_date": "2026-08-21T00:42:22Z",
      "product_status:known_affected": "284",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-72220",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-72220.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.

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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 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.


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