GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

FKIE_CVE-2025-39758

Vulnerability from fkie_nvd - Published: 2025-09-11 17:15 - Updated: 2026-08-23 13:16
Severity
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: RDMA/siw: Fix the sendmsg byte count in siw_tcp_sendpages Ever since commit c2ff29e99a76 ("siw: Inline do_tcp_sendpages()"), we have been doing this: static int siw_tcp_sendpages(struct socket *s, struct page **page, int offset, size_t size) [...] /* Calculate the number of bytes we need to push, for this page * specifically */ size_t bytes = min_t(size_t, PAGE_SIZE - offset, size); /* If we can't splice it, then copy it in, as normal */ if (!sendpage_ok(page[i])) msg.msg_flags &= ~MSG_SPLICE_PAGES; /* Set the bvec pointing to the page, with len $bytes */ bvec_set_page(&bvec, page[i], bytes, offset); /* Set the iter to $size, aka the size of the whole sendpages (!!!) */ iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1, size); try_page_again: lock_sock(sk); /* Sendmsg with $size size (!!!) */ rv = tcp_sendmsg_locked(sk, &msg, size); This means we've been sending oversized iov_iters and tcp_sendmsg calls for a while. This has a been a benign bug because sendpage_ok() always returned true. With the recent slab allocator changes being slowly introduced into next (that disallow sendpage on large kmalloc allocations), we have recently hit out-of-bounds crashes, due to slight differences in iov_iter behavior between the MSG_SPLICE_PAGES and "regular" copy paths: (MSG_SPLICE_PAGES) skb_splice_from_iter iov_iter_extract_pages iov_iter_extract_bvec_pages uses i->nr_segs to correctly stop in its tracks before OoB'ing everywhere skb_splice_from_iter gets a "short" read (!MSG_SPLICE_PAGES) skb_copy_to_page_nocache copy=iov_iter_count [...] copy_from_iter /* this doesn't help */ if (unlikely(iter->count < len)) len = iter->count; iterate_bvec ... and we run off the bvecs Fix this by properly setting the iov_iter's byte count, plus sending the correct byte count to tcp_sendmsg_locked.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/42ebc16d9d2563f1a1ce0f05b643ee68d54fabf8Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5661fdd218c2799001b88c17acd19f4395e4488ePatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/673cf582fd788af12cdacfb62a6a593083542481Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b47c4b7cb78b6382c6d1af0bfc0d8218e4f445cc
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c18646248fed07683d4cee8a8af933fc4fe83c0dPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/edf82bc8150570167a33a7d54627d66614cbf841Patch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/infiniband/sw/siw/siw_qp_tx.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "b47c4b7cb78b6382c6d1af0bfc0d8218e4f445cc",
              "status": "affected",
              "version": "a19a58ab12695abb91a4e8ecf62cc0bc5badefbe",
              "versionType": "git"
            },
            {
              "lessThan": "5661fdd218c2799001b88c17acd19f4395e4488e",
              "status": "affected",
              "version": "c2ff29e99a764769eb2ce3a1a5585013633ee9a6",
              "versionType": "git"
            },
            {
              "lessThan": "673cf582fd788af12cdacfb62a6a593083542481",
              "status": "affected",
              "version": "c2ff29e99a764769eb2ce3a1a5585013633ee9a6",
              "versionType": "git"
            },
            {
              "lessThan": "42ebc16d9d2563f1a1ce0f05b643ee68d54fabf8",
              "status": "affected",
              "version": "c2ff29e99a764769eb2ce3a1a5585013633ee9a6",
              "versionType": "git"
            },
            {
              "lessThan": "edf82bc8150570167a33a7d54627d66614cbf841",
              "status": "affected",
              "version": "c2ff29e99a764769eb2ce3a1a5585013633ee9a6",
              "versionType": "git"
            },
            {
              "lessThan": "c18646248fed07683d4cee8a8af933fc4fe83c0d",
              "status": "affected",
              "version": "c2ff29e99a764769eb2ce3a1a5585013633ee9a6",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/infiniband/sw/siw/siw_qp_tx.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.5"
            },
            {
              "lessThan": "6.5",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.103",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.43",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.15.*",
              "status": "unaffected",
              "version": "6.15.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.16.*",
              "status": "unaffected",
              "version": "6.16.2",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.17",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "A0671C86-DE03-40C0-BDE5-B2242961ACA8",
              "versionEndExcluding": "6.6.103",
              "versionStartIncluding": "6.5",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "472C5F87-2BF3-4FAB-9B21-DA7513977363",
              "versionEndExcluding": "6.12.43",
              "versionStartIncluding": "6.7",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "BC242347-F722-43AE-B910-BE0B22386977",
              "versionEndExcluding": "6.15.11",
              "versionStartIncluding": "6.13",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "BD7C087D-2415-4521-B624-30003352F899",
              "versionEndExcluding": "6.16.2",
              "versionStartIncluding": "6.16",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/siw: Fix the sendmsg byte count in siw_tcp_sendpages\n\nEver since commit c2ff29e99a76 (\"siw: Inline do_tcp_sendpages()\"),\nwe have been doing this:\n\nstatic int siw_tcp_sendpages(struct socket *s, struct page **page, int offset,\n                             size_t size)\n[...]\n        /* Calculate the number of bytes we need to push, for this page\n         * specifically */\n        size_t bytes = min_t(size_t, PAGE_SIZE - offset, size);\n        /* If we can\u0027t splice it, then copy it in, as normal */\n        if (!sendpage_ok(page[i]))\n                msg.msg_flags \u0026= ~MSG_SPLICE_PAGES;\n        /* Set the bvec pointing to the page, with len $bytes */\n        bvec_set_page(\u0026bvec, page[i], bytes, offset);\n        /* Set the iter to $size, aka the size of the whole sendpages (!!!) */\n        iov_iter_bvec(\u0026msg.msg_iter, ITER_SOURCE, \u0026bvec, 1, size);\ntry_page_again:\n        lock_sock(sk);\n        /* Sendmsg with $size size (!!!) */\n        rv = tcp_sendmsg_locked(sk, \u0026msg, size);\n\nThis means we\u0027ve been sending oversized iov_iters and tcp_sendmsg calls\nfor a while. This has a been a benign bug because sendpage_ok() always\nreturned true. With the recent slab allocator changes being slowly\nintroduced into next (that disallow sendpage on large kmalloc\nallocations), we have recently hit out-of-bounds crashes, due to slight\ndifferences in iov_iter behavior between the MSG_SPLICE_PAGES and\n\"regular\" copy paths:\n\n(MSG_SPLICE_PAGES)\nskb_splice_from_iter\n  iov_iter_extract_pages\n    iov_iter_extract_bvec_pages\n      uses i-\u003enr_segs to correctly stop in its tracks before OoB\u0027ing everywhere\n  skb_splice_from_iter gets a \"short\" read\n\n(!MSG_SPLICE_PAGES)\nskb_copy_to_page_nocache copy=iov_iter_count\n [...]\n   copy_from_iter\n        /* this doesn\u0027t help */\n        if (unlikely(iter-\u003ecount \u003c len))\n                len = iter-\u003ecount;\n          iterate_bvec\n            ... and we run off the bvecs\n\nFix this by properly setting the iov_iter\u0027s byte count, plus sending the\ncorrect byte count to tcp_sendmsg_locked."
    }
  ],
  "id": "CVE-2025-39758",
  "lastModified": "2026-08-23T13:16:26.380",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      },
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2025-09-11T17:15:39.663",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/42ebc16d9d2563f1a1ce0f05b643ee68d54fabf8"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/5661fdd218c2799001b88c17acd19f4395e4488e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/673cf582fd788af12cdacfb62a6a593083542481"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b47c4b7cb78b6382c6d1af0bfc0d8218e4f445cc"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/c18646248fed07683d4cee8a8af933fc4fe83c0d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/edf82bc8150570167a33a7d54627d66614cbf841"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





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

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.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.