{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "0.9.0"
                  },
                  {
                    "fixed": "2.5.0"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              },
              {
                "range": [
                  {
                    "fixed": "90f4e7c3ebe4cf9a5eb7d981220388ffdefd6d19"
                  }
                ],
                "source": "REFERENCES_COMMIT"
              }
            ]
          },
          "events": [
            {
              "introduced": "b6efee9deb9d748cb2f0856a520becc67d808214"
            },
            {
              "fixed": "725d63c9d5bc1bb572d802e7a768daf504186daf"
            },
            {
              "fixed": "90f4e7c3ebe4cf9a5eb7d981220388ffdefd6d19"
            }
          ],
          "repo": "https://github.com/mcu-tools/mcuboot",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-4fp3-3qw2-25jv"
  ],
  "database_specific": {
    "cna_assigner": "zephyr",
    "cwe_ids": [
      "CWE-125"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/127xxx/CVE-2026-127915.json"
  },
  "details": "The MCUboot TLV iterator bootutil_tlv_iter_next() in boot/bootutil/src/tlv.c walks image trailer TLVs with a single loop guard (it-\u003etlv_off \u003c it-\u003etlv_end) and advances by sizeof(struct image_tlv) + tlv.it_len using the attacker-controlled it_len field, without validating that the entry's header or payload stays within it-\u003etlv_end. As a result the 4-byte header read can extend up to 3 bytes past the declared TLV area, and the returned (off, len) can describe a payload that runs past it.\n\nThe path is pre-authentication: TLVs are parsed during bootutil_img_validate() before the signature is verified, and a crafted image can be presented through DFU / serial-recovery / OTA. However the impact is contained by surrounding guards: bootutil_img_validate() first rejects a TLV area larger than bootutil_max_image_size(), the default LOAD_IMAGE_DATA sink is flash_area_read() which bounds-checks against the flash partition and fails an out-of-partition read, and every payload consumer (EXPECTED_HASH_TLV, EXPECTED_KEY_TLV, EXPECTED_SIG_TLV, IMAGE_TLV_SEC_CNT) clamps len against a fixed buffer before copying.\n\nThe residual effect in a default flash build is therefore an out-of-region read confined to the attacker's own slot partition whose result is never observable, yielding at worst a clean validation failure rather than memory corruption or information disclosure. A genuine (though still bounded) out-of-bounds read remains under the non-default MCUBOOT_RAM_LOAD configuration, where LOAD_IMAGE_DATA is an unchecked memcpy. The fix is to validate each entry's header and payload against it-\u003etlv_end inside the iterator.",
  "id": "CVE-2026-127915",
  "modified": "2026-11-14T02:30:16.209736822Z",
  "published": "2026-11-13T00:23:07.449Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/127xxx/CVE-2026-127915.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/mcu-tools/mcuboot/security/advisories/GHSA-4fp3-3qw2-25jv"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-127915"
    },
    {
      "type": "FIX",
      "url": "https://github.com/mcu-tools/mcuboot/commit/90f4e7c3ebe4cf9a5eb7d981220388ffdefd6d19"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/mcu-tools/mcuboot"
    }
  ],
  "schema_version": "1.9.2",
  "severity": [
    {
      "score": "CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "TLV iterator does not bound each entry against the declared TLV area in MCUboot bootutil"
}