CVE-2026-74429 (GCVE-0-2026-74429)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:59 – Updated: 2026-08-17 05:47
VLAI
Title
rxrpc: Fix the reception of a reply packet before data transmission
Summary
In the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix the reception of a reply packet before data transmission Fix rxrpc_receiving_reply() to handle the reception of an apparent reply DATA packet before rxrpc has had a chance to send any request DATA packets on a client call by checking to see if the call has been exposed yet by sending the first packet. Without this, rxrpc_rotate_tx_window() might oops. Also fix rxrpc_rotate_tx_window() to handle the Tx queue being empty by changing the do...while loop into a while loop, just in case a call is abnormally terminated by an early reply before the last request packet is transmitted.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: b341a0263b1b804d329f864c2dc24815364510ec , < f9be514984471ff0003738b2e1efed12bc3433ff (git)
Affected: b341a0263b1b804d329f864c2dc24815364510ec , < e220ae559e5a0fc33e41ec6a348ea50387cb8b0f (git)
Affected: b341a0263b1b804d329f864c2dc24815364510ec , < a58e33405acd2584e730c1da72635f822ada6b49 (git)
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Linux Linux Affected: 6.14
Unaffected: 0 , < 6.14 (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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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/rxrpc/input.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
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              "versionType": "semver"
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              "operator": "OR"
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        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc: Fix the reception of a reply packet before data transmission\n\nFix rxrpc_receiving_reply() to handle the reception of an apparent reply\nDATA packet before rxrpc has had a chance to send any request DATA packets\non a client call by checking to see if the call has been exposed yet by\nsending the first packet.\n\nWithout this, rxrpc_rotate_tx_window() might oops.\n\nAlso fix rxrpc_rotate_tx_window() to handle the Tx queue being empty by\nchanging the do...while loop into a while loop, just in case a call is\nabnormally terminated by an early reply before the last request packet is\ntransmitted."
        }
      ],
      "metrics": [
        {
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            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The bug is reached when a remote UDP RxRPC DATA reply is processed on an established client call via rxrpc_encap_rcv(), rxrpc_input_packet_on_conn(), and rxrpc_input_data(); a malicious or compromised AFS/RxRPC server peer can send that early reply over the network to any kAFS/AF_RXRPC client.\nAC:L - The remote server controls both sides of the timing race\u2014it can send a reply DATA packet immediately after the client call is live on the channel but before RXRPC_CALL_EXPOSED/first transmit\u2014and can retry on every RPC without depending on memory layout or other uncontrollable conditions.\nPR:N - No local credentials or kernel capabilities on the victim are required; exploitation only needs the attacker to act as the established RxRPC server peer able to send call-bound DATA packets on an active client connection after the normal security handshake.\nUI:N - Once the victim host has an active client call (normal kAFS file access or AF_RXRPC sendmsg), the kernel rxrpc I/O thread autonomously processes the attacker\u0027s early reply with no further interactive victim action at exploit time.\nS:U - The oops in rxrpc_rotate_tx_window() affects only kernel memory and threads within the same security authority on the client host; it does not cross VM, container, IOMMU, or sandbox boundaries.\nC:N - The defect is a NULL dereference from a do...while loop that executes once on an empty Tx queue when seq exceeds tx_top (tq or tq-\u003ebufs[ix] is NULL); this is a pure crash path, not an out-of-bounds read or use-after-free disclosure primitive.\nI:N - No attacker-controlled memory is written; the failure dereferences NULL or uninitialized txqueue entries before any buffer rotation or put_txbuf logic completes, yielding only a kernel fault without integrity modification capability.\nA:H - Without the fix, rxrpc_rotate_tx_window() oopses the rxrpc I/O kernel thread that services all RxRPC/AFS traffic on that endpoint; a malicious server can trigger this on every client RPC call, causing repeated kernel crashes or hangs."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:47:04.412Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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        },
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          "url": "https://git.kernel.org/stable/c/e220ae559e5a0fc33e41ec6a348ea50387cb8b0f"
        },
        {
          "url": "https://git.kernel.org/stable/c/a58e33405acd2584e730c1da72635f822ada6b49"
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      "title": "rxrpc: Fix the reception of a reply packet before data transmission",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74429",
    "datePublished": "2026-08-15T05:59:30.286Z",
    "dateReserved": "2026-08-15T05:44:03.895Z",
    "dateUpdated": "2026-08-17T05:47:04.412Z",
    "state": "PUBLISHED"
  },
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      "date": "2026-09-21",
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      "percentile": "0.26856"
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          }
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        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc: Fix the reception of a reply packet before data transmission\n\nFix rxrpc_receiving_reply() to handle the reception of an apparent reply\nDATA packet before rxrpc has had a chance to send any request DATA packets\non a client call by checking to see if the call has been exposed yet by\nsending the first packet.\n\nWithout this, rxrpc_rotate_tx_window() might oops.\n\nAlso fix rxrpc_rotate_tx_window() to handle the Tx queue being empty by\nchanging the do...while loop into a while loop, just in case a call is\nabnormally terminated by an early reply before the last request packet is\ntransmitted."
          }
        ],
        "id": "CVE-2026-74429",
        "lastModified": "2026-08-17T06:19:38.487",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 7.5,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "NONE",
                "integrityImpact": "NONE",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                "version": "3.1"
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              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
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        "published": "2026-08-15T06:22:45.027",
        "references": [
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            "url": "https://git.kernel.org/stable/c/a58e33405acd2584e730c1da72635f822ada6b49"
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        "vulnStatus": "Received"
      }
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-20T22:41:39+00:00",
      "cve": "CVE-2026-74429",
      "id": "CVE-2026-74429",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_affected": "76",
      "product_status:known_not_affected": "198",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: rxrpc: Fix the reception of a reply packet before data transmission",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74429.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.
  • 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.


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