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CVE-2026-64025 (GCVE-0-2026-64025)

Vulnerability from cvelistv5 – Published: 2026-07-19 15:39 – Updated: 2026-08-05 12:38
VLAI
Title
bpf, skmsg: fix verdict sk_data_ready racing with ktls rx
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf, skmsg: fix verdict sk_data_ready racing with ktls rx sk_psock_strp_data_ready() already checks tls_sw_has_ctx_rx() and defers to psock->saved_data_ready when a TLS RX context is present, avoiding a conflict with the TLS strparser's ownership of the receive queue (commit e91de6afa81c, "bpf: Fix running sk_skb program types with ktls"). sk_psock_verdict_data_ready() has no equivalent guard. When a socket is inserted into a sockmap (BPF_SK_SKB_VERDICT) before TLS RX is configured, tls_sw_strparser_arm() saves sk_psock_verdict_data_ready as rx_ctx->saved_data_ready. On data arrival: tls_data_ready -> tls_strp_data_ready -> tls_rx_msg_ready -> saved_data_ready() = sk_psock_verdict_data_ready() -> tcp_read_skb() drains sk_receive_queue via __skb_unlink() without calling tcp_eat_skb(), so copied_seq is not advanced. tls_strp_msg_load() then finds tcp_inq() >= full_len (stale), calls tcp_recv_skb() on the now-empty queue, hits WARN_ON_ONCE(!first), and returns with rx_ctx->strp.anchor.frag_list pointing at a psock-owned (potentially freed) skb. tls_decrypt_sg() subsequently walks that frag_list: use-after-free. Apply the same fix as sk_psock_strp_data_ready(): if a TLS RX context is present, call psock->saved_data_ready (sock_def_readable) to wake recv() waiters and return immediately, leaving the receive queue untouched. TLS retains sole ownership of the queue and decrypts the record normally through tls_sw_recvmsg().
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: ef5659280eb13e8ac31c296f58cfdfa1684ac06b , < c9ea01768903ae47f210cd457af1dead6de7a9c3 (git)
Affected: ef5659280eb13e8ac31c296f58cfdfa1684ac06b , < 7c8cf21bc4efb4af18d6096db3f8bd06d622251c (git)
Affected: ef5659280eb13e8ac31c296f58cfdfa1684ac06b , < 1861d369efd62d67796563bf3e01fc22e5626f8b (git)
Affected: ef5659280eb13e8ac31c296f58cfdfa1684ac06b , < 8a52139560f833c3975032e1f5762611e3a36d71 (git)
Affected: ef5659280eb13e8ac31c296f58cfdfa1684ac06b , < ddf8029623a1af20e984c040e89ff918158397ab (git)
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Linux Linux Affected: 5.10
Unaffected: 0 , < 5.10 (semver)
Unaffected: 6.6.142 , ≤ 6.6.* (semver)
Unaffected: 6.12.92 , ≤ 6.12.* (semver)
Unaffected: 6.18.34 , ≤ 6.18.* (semver)
Unaffected: 7.0.11 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
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{
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          "product": "Linux",
          "programFiles": [
            "net/core/skmsg.c"
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        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf, skmsg: fix verdict sk_data_ready racing with ktls rx\n\nsk_psock_strp_data_ready() already checks tls_sw_has_ctx_rx() and\ndefers to psock-\u003esaved_data_ready when a TLS RX context is present,\navoiding a conflict with the TLS strparser\u0027s ownership of the receive\nqueue (commit e91de6afa81c, \"bpf: Fix running sk_skb program types\nwith ktls\").\n\nsk_psock_verdict_data_ready() has no equivalent guard.  When a socket\nis inserted into a sockmap (BPF_SK_SKB_VERDICT) before TLS RX is\nconfigured, tls_sw_strparser_arm() saves sk_psock_verdict_data_ready\nas rx_ctx-\u003esaved_data_ready.  On data arrival:\n\n  tls_data_ready -\u003e tls_strp_data_ready -\u003e tls_rx_msg_ready\n    -\u003e saved_data_ready() = sk_psock_verdict_data_ready()\n      -\u003e tcp_read_skb() drains sk_receive_queue via __skb_unlink()\n         without calling tcp_eat_skb(), so copied_seq is not advanced.\n\ntls_strp_msg_load() then finds tcp_inq() \u003e= full_len (stale), calls\ntcp_recv_skb() on the now-empty queue, hits WARN_ON_ONCE(!first), and\nreturns with rx_ctx-\u003estrp.anchor.frag_list pointing at a psock-owned\n(potentially freed) skb.  tls_decrypt_sg() subsequently walks that\nfrag_list: use-after-free.\n\nApply the same fix as sk_psock_strp_data_ready(): if a TLS RX context\nis present, call psock-\u003esaved_data_ready (sock_def_readable) to wake\nrecv() waiters and return immediately, leaving the receive queue\nuntouched.  TLS retains sole ownership of the queue and decrypts the\nrecord normally through tls_sw_recvmsg()."
        }
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            "version": "3.1"
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              "value": "AV:N - The UAF is triggered on the kTLS software RX path when a remote TLS peer sends TCP data; inbound network packets drive tls_data_ready through to sk_psock_verdict_data_ready and tls_decrypt_sg on internet-facing eBPF/kTLS proxy servers.\nAC:L - Once the sockmap-before-TLS-RX configuration exists, the bug fires deterministically on the first arriving TLS record; the attacker controls packet delivery and timing without needing to win an uncontrollable race.\nPR:N - A remote unauthenticated TLS client needs no privileges on the victim host to trigger the bug on a server already running BPF sockmap verdict with kTLS RX; local exploitation via user namespaces only raises the bar to CAP_NET_ADMIN/CAP_BPF (PR:L), not higher.\nUI:N - Exploitation requires only sending TLS traffic to a vulnerable socket; no victim user action such as opening files or mounting filesystems is needed.\nS:U - Impact is kernel heap corruption within the host kernel security boundary; it does not inherently cross VM, container, or IOMMU isolation boundaries without separate escalation.\nC:H - The bug is a use-after-free where tls_decrypt_sg() walks a dangling skb frag_list via skb_to_sgvec/skb_copy_bits, enabling arbitrary kernel memory read primitives from attacker-influenced freed heap objects.\nI:H - Heap UAF over sk_buff structures in the TLS decrypt path can be leveraged for arbitrary kernel memory writes and control-flow hijacking, not merely a bounded or transient corruption.\nA:H - The failure path hits WARN_ON_ONCE in tls_strp_load_anchor_with_queue and the UAF in tls_decrypt_sg can cause kernel oops, panic, or crash during softirq TLS receive processing."
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64025",
    "datePublished": "2026-07-19T15:39:17.178Z",
    "dateReserved": "2026-07-19T07:54:57.027Z",
    "dateUpdated": "2026-08-05T12:38:19.891Z",
    "state": "PUBLISHED"
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On data arrival:\\n\\n  tls_data_ready -\u003e tls_strp_data_ready -\u003e tls_rx_msg_ready\\n    -\u003e saved_data_ready() = sk_psock_verdict_data_ready()\\n      -\u003e tcp_read_skb() drains sk_receive_queue via __skb_unlink()\\n         without calling tcp_eat_skb(), so copied_seq is not advanced.\\n\\ntls_strp_msg_load() then finds tcp_inq() \u003e= full_len (stale), calls\\ntcp_recv_skb() on the now-empty queue, hits WARN_ON_ONCE(!first), and\\nreturns with rx_ctx-\u003estrp.anchor.frag_list pointing at a psock-owned\\n(potentially freed) skb.  tls_decrypt_sg() subsequently walks that\\nfrag_list: use-after-free.\\n\\nApply the same fix as sk_psock_strp_data_ready(): if a TLS RX context\\nis present, call psock-\u003esaved_data_ready (sock_def_readable) to wake\\nrecv() waiters and return immediately, leaving the receive queue\\nuntouched.  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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-05T14:20:45+00:00",
      "cve": "CVE-2026-64025",
      "id": "CVE-2026-64025",
      "initial_release_date": "2026-07-19T00:00:00+00:00",
      "product_status:known_affected": "232",
      "product_status:known_not_affected": "43",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: bpf, skmsg: fix verdict sk_data_ready racing with ktls rx",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64025.json",
      "version": "3"
    }
  }
}



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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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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.
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