CVE-2026-31636 (GCVE-0-2026-31636)
Vulnerability from cvelistv5
Published
2026-04-24 14:44
Modified
2026-08-05 12:24
Severity ?
9.1 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: rxrpc: fix RESPONSE authenticator parser OOB read rxgk_verify_authenticator() copies auth_len bytes into a temporary buffer and then passes p + auth_len as the parser limit to rxgk_do_verify_authenticator(). Since p is a __be32 *, that inflates the parser end pointer by a factor of four and lets malformed RESPONSE authenticators read past the kmalloc() buffer. Decoded from the original latest-net reproduction logs with scripts/decode_stacktrace.sh: BUG: KASAN: slab-out-of-bounds in rxgk_verify_response() Call Trace: dump_stack_lvl() [lib/dump_stack.c:123] print_report() [mm/kasan/report.c:379 mm/kasan/report.c:482] kasan_report() [mm/kasan/report.c:597] rxgk_verify_response() [net/rxrpc/rxgk.c:1103 net/rxrpc/rxgk.c:1167 net/rxrpc/rxgk.c:1274] rxrpc_process_connection() [net/rxrpc/conn_event.c:266 net/rxrpc/conn_event.c:364 net/rxrpc/conn_event.c:386] process_one_work() [kernel/workqueue.c:3281] worker_thread() [kernel/workqueue.c:3353 kernel/workqueue.c:3440] kthread() [kernel/kthread.c:436] ret_from_fork() [arch/x86/kernel/process.c:164] Allocated by task 54: rxgk_verify_response() [include/linux/slab.h:954 net/rxrpc/rxgk.c:1155 net/rxrpc/rxgk.c:1274] rxrpc_process_connection() [net/rxrpc/conn_event.c:266 net/rxrpc/conn_event.c:364 net/rxrpc/conn_event.c:386] Convert the byte count to __be32 units before constructing the parser limit.
References
Impacted products
Vendor Product Version
Linux Linux Version: 9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a
Version: 9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a
Version: 9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/rxrpc/rxgk.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "lessThan": "7875f3d9777bd4e9892c4db830571ab8ac2044c0",
              "status": "affected",
              "version": "9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a",
              "versionType": "git"
            },
            {
              "lessThan": "20a188775a9a9982d1987e12660d9b44b40a6c99",
              "status": "affected",
              "version": "9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a",
              "versionType": "git"
            },
            {
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              "status": "affected",
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              "versionType": "git"
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        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/rxrpc/rxgk.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "lessThan": "6.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.23",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.13",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.23",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.13",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc: fix RESPONSE authenticator parser OOB read\n\nrxgk_verify_authenticator() copies auth_len bytes into a temporary\nbuffer and then passes p + auth_len as the parser limit to\nrxgk_do_verify_authenticator(). Since p is a __be32 *, that inflates the\nparser end pointer by a factor of four and lets malformed RESPONSE\nauthenticators read past the kmalloc() buffer.\n\nDecoded from the original latest-net reproduction logs with\nscripts/decode_stacktrace.sh:\n\nBUG: KASAN: slab-out-of-bounds in rxgk_verify_response()\nCall Trace:\n dump_stack_lvl() [lib/dump_stack.c:123]\n print_report() [mm/kasan/report.c:379 mm/kasan/report.c:482]\n kasan_report() [mm/kasan/report.c:597]\n rxgk_verify_response()\n   [net/rxrpc/rxgk.c:1103 net/rxrpc/rxgk.c:1167\n    net/rxrpc/rxgk.c:1274]\n rxrpc_process_connection()\n   [net/rxrpc/conn_event.c:266 net/rxrpc/conn_event.c:364\n    net/rxrpc/conn_event.c:386]\n process_one_work() [kernel/workqueue.c:3281]\n worker_thread()\n   [kernel/workqueue.c:3353 kernel/workqueue.c:3440]\n kthread() [kernel/kthread.c:436]\n ret_from_fork() [arch/x86/kernel/process.c:164]\n\nAllocated by task 54:\n rxgk_verify_response()\n   [include/linux/slab.h:954 net/rxrpc/rxgk.c:1155\n    net/rxrpc/rxgk.c:1274]\n rxrpc_process_connection()\n   [net/rxrpc/conn_event.c:266 net/rxrpc/conn_event.c:364\n    net/rxrpc/conn_event.c:386]\n\nConvert the byte count to __be32 units before constructing the parser\nlimit."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.1,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The vulnerable rxgk RESPONSE authenticator parser is reached by network RxRPC packets delivered over UDP to an AF_RXRPC service connection.\nAC:L - There is no race or condition outside the attacker\u0027s control; a peer can initiate the handshake, receive the challenge, and send malformed RESPONSE data to drive the parser.\nPR:N - The packet is processed while the server connection is still in RXRPC_CONN_SERVICE_CHALLENGING, before the connection is accepted as authenticated.\nUI:N - No victim user action is required beyond the RxRPC service being reachable and processing incoming network traffic.\nS:U - The impact remains within the kernel/RxRPC service security authority and does not cross a VM, IOMMU, or comparable scope boundary.\nC:H - The byte-count versus __be32 pointer arithmetic bug lets the parser read well beyond the kmalloc authenticator buffer at attacker-influenced offsets, and the overread is not strictly bounded to a few bytes.\nI:N - The flaw is an out-of-bounds read and does not provide an arbitrary write or control-flow modification primitive.\nA:H - The fix commit documents a KASAN slab-out-of-bounds report in the RESPONSE processing path, and malformed network responses can repeatedly trigger kernel fault/panic behavior."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:24:00.729Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/7875f3d9777bd4e9892c4db830571ab8ac2044c0"
        },
        {
          "url": "https://git.kernel.org/stable/c/20a188775a9a9982d1987e12660d9b44b40a6c99"
        },
        {
          "url": "https://git.kernel.org/stable/c/3e3138007887504ee9206d0bfb5acb062c600025"
        }
      ],
      "title": "rxrpc: fix RESPONSE authenticator parser OOB read",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-31636",
    "datePublished": "2026-04-24T14:44:50.637Z",
    "dateReserved": "2026-03-09T15:48:24.125Z",
    "dateUpdated": "2026-08-05T12:24:00.729Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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