FKIE_CVE-2026-10773

Vulnerability from fkie_nvd - Published: 2026-08-01 13:16 - Updated: 2026-09-01 00:16
Severity
5.4 (Medium) - CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
Summary
The DHCPv4 client helper net_dhcpv4_msg_type_name() in subsys/net/lib/dhcpv4/dhcpv4.c indexes a static 8-element const char * name table after a faulty bounds check. The guard used msg_type <= sizeof(name) instead of msg_type <= ARRAY_SIZE(name); sizeof returns the byte size of the pointer array (32 on 32-bit, 64 on 64-bit targets) rather than the element count of 8, so message-type values from 9 up to that byte size pass the check and cause name[msg_type - 1] to read past the end of the array. The msg_type value originates from the DHCP MESSAGE TYPE option, which is read as an unchecked raw byte from a received packet (net_pkt_read_u8) and passed unmodified into the lookup. A DHCP server, or any host able to inject a spoofed DHCP reply onto the client's link, can therefore drive the index out of bounds. The out-of-range slot yields a garbage const char * that is then dereferenced by a %s log conversion. The lookup is reached only from a debug log statement (NET_DBG / LOG_DBG), so the out-of-bounds read is triggerable only when the DHCPv4 log module is built at DEBUG level (CONFIG_NET_DHCPV4_LOG_LEVEL_DBG), which is not the default configuration. When that condition holds, the result is an out-of-bounds read and a wild-pointer dereference: most likely a crash of the DHCP client (denial of service) and potentially disclosure of an adjacent pointer's contents through the log output. The fix replaces sizeof with ARRAY_SIZE, restoring the correct 1..8 acceptance window.
References
vulnerabilities@zephyrproject.orghttps://github.com/zephyrproject-rtos/zephyr/commit/73c8a7df4f00088fc04ee5ab71bcabf47fcd3db7Patch
vulnerabilities@zephyrproject.orghttps://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-r5hq-xq42-wcfqExploit, Patch, Vendor Advisory
134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-r5hq-xq42-wcfqExploit, Patch, Vendor Advisory
Impacted products
Vendor Product Version
zephyrproject zephyr *
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "collectionURL": "https://github.com/zephyrproject-rtos/zephyr",
          "defaultStatus": "unaffected",
          "packageName": "zephyr",
          "product": "zephyr",
          "programFiles": [
            "subsys/net/lib/dhcpv4/dhcpv4.c",
            "subsys/net/lib/dhcpv6/dhcpv6.c"
          ],
          "vendor": "zephyrproject",
          "versions": [
            {
              "lessThan": "4.4.2",
              "status": "affected",
              "version": "1.7.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "vulnerabilities@zephyrproject.org"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:zephyrproject:zephyr:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "DD732473-E0F3-4E27-AD8B-983D7D9C10D6",
              "versionEndExcluding": "4.5.0",
              "versionStartIncluding": "3.6.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "The DHCPv4 client helper net_dhcpv4_msg_type_name() in subsys/net/lib/dhcpv4/dhcpv4.c indexes a static 8-element const char * name table after a faulty bounds check. The guard used msg_type \u003c= sizeof(name) instead of msg_type \u003c= ARRAY_SIZE(name); sizeof returns the byte size of the pointer array (32 on 32-bit, 64 on 64-bit targets) rather than the element count of 8, so message-type values from 9 up to that byte size pass the check and cause name[msg_type - 1] to read past the end of the array.\n\nThe msg_type value originates from the DHCP MESSAGE TYPE option, which is read as an unchecked raw byte from a received packet (net_pkt_read_u8) and passed unmodified into the lookup. A DHCP server, or any host able to inject a spoofed DHCP reply onto the client\u0027s link, can therefore drive the index out of bounds. The out-of-range slot yields a garbage const char * that is then dereferenced by a %s log conversion.\n\nThe lookup is reached only from a debug log statement (NET_DBG / LOG_DBG), so the out-of-bounds read is triggerable only when the DHCPv4 log module is built at DEBUG level (CONFIG_NET_DHCPV4_LOG_LEVEL_DBG), which is not the default configuration. When that condition holds, the result is an out-of-bounds read and a wild-pointer dereference: most likely a crash of the DHCP client (denial of service) and potentially disclosure of an adjacent pointer\u0027s contents through the log output. The fix replaces sizeof with ARRAY_SIZE, restoring the correct 1..8 acceptance window."
    }
  ],
  "id": "CVE-2026-10773",
  "lastModified": "2026-09-01T00:16:39.683",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "ADJACENT_NETWORK",
          "availabilityImpact": "LOW",
          "baseScore": 5.4,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "LOW",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 2.5,
        "source": "vulnerabilities@zephyrproject.org",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-10773",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-03T17:50:29.274490Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-01T13:16:56.987",
  "references": [
    {
      "source": "vulnerabilities@zephyrproject.org",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/zephyrproject-rtos/zephyr/commit/73c8a7df4f00088fc04ee5ab71bcabf47fcd3db7"
    },
    {
      "source": "vulnerabilities@zephyrproject.org",
      "tags": [
        "Exploit",
        "Patch",
        "Vendor Advisory"
      ],
      "url": "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-r5hq-xq42-wcfq"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "tags": [
        "Exploit",
        "Patch",
        "Vendor Advisory"
      ],
      "url": "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-r5hq-xq42-wcfq"
    }
  ],
  "sourceIdentifier": "vulnerabilities@zephyrproject.org",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-125"
        },
        {
          "lang": "en",
          "value": "CWE-682"
        }
      ],
      "source": "vulnerabilities@zephyrproject.org",
      "type": "Secondary"
    },
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-125"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}



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