OESA-2026-2833 (CVE-2026-48487)

Vulnerability from osv_openeuler – Published: 2026-07-06 11:11 – Updated: 2026-08-06 11:11 – Source website
VLAI
Summary
python-zeroconf security update
Details

Pure Python Multicast DNS Service Discovery Library (Bonjour/Avahi compatible)

Security Fix(es):

_read_character_string and _read_string in src/zeroconf/_protocol/incoming.py sliced self.data[self.offset : self.offset + length] and advanced self.offset by the declared length without checking it against self._data_len. Python's slice silently returns fewer bytes when the end index runs past the buffer, so a record whose 16-bit RDLENGTH (RFC 1035 §3.2.1) over-advertised by tens of kilobytes was constructed from a truncated payload, appended to DNSIncoming._answers, and committed to the cache before any later parse failure surfaced. Any unauthenticated host on the local link (UDP/5353, 224.0.0.251 / ff02::fb) can multicast a single mDNS response carrying a TXT, HINFO, or A/AAAA record that advertises rdlength=65535 and only a handful of real payload bytes; consumers calling ServiceInfo.properties then parse the truncated bytes as if they matched the wire, and downstream integrations (Home Assistant and other zeroconf-driven discovery) trust the decoded record. The bug is parser-state desync rather than RCE, but it seeds the cache with attacker-shaped key/value and address records for a TTL window and is a building block for higher-impact chains.(CVE-2026-48487)

Severity
6.5 (Medium)
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "noarch": [
          "python-zeroconf-help-0.131.0-2.oe2403sp3.noarch.rpm",
          "python3-zeroconf-0.131.0-2.oe2403sp3.noarch.rpm"
        ],
        "src": [
          "python-zeroconf-0.131.0-2.oe2403sp3.src.rpm"
        ]
      },
      "package": {
        "ecosystem": "openEuler:24.03-LTS-SP3",
        "name": "python-zeroconf",
        "purl": "pkg:rpm/openEuler/python-zeroconf\u0026distro=openEuler-24.03-LTS-SP3"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.131.0-2.oe2403sp3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "severity": "Medium"
  },
  "details": "Pure Python Multicast DNS Service Discovery Library (Bonjour/Avahi compatible)\r\n\r\nSecurity Fix(es):\n\n`_read_character_string` and `_read_string` in `src/zeroconf/_protocol/incoming.py` sliced `self.data[self.offset : self.offset + length]` and advanced `self.offset` by the declared `length` without checking it against `self._data_len`. Python\u0026apos;s slice silently returns fewer bytes when the end index runs past the buffer, so a record whose 16-bit RDLENGTH (RFC 1035 \u00a73.2.1) over-advertised by tens of kilobytes was constructed from a truncated payload, appended to `DNSIncoming._answers`, and committed to the cache before any later parse failure surfaced. Any unauthenticated host on the local link (UDP/5353, 224.0.0.251 / ff02::fb) can multicast a single mDNS response carrying a TXT, HINFO, or A/AAAA record that advertises rdlength=65535 and only a handful of real payload bytes; consumers calling `ServiceInfo.properties` then parse the truncated bytes as if they matched the wire, and downstream integrations (Home Assistant and other zeroconf-driven discovery) trust the decoded record. The bug is parser-state desync rather than RCE, but it seeds the cache with attacker-shaped key/value and address records for a TTL window and is a building block for higher-impact chains.(CVE-2026-48487)",
  "id": "OESA-2026-2833",
  "modified": "2026-08-06T11:11:45Z",
  "published": "2026-07-06T11:11:45Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2026-2833"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-48487"
    }
  ],
  "schema_version": "1.7.2",
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "python-zeroconf security update",
  "upstream": [
    "CVE-2026-48487"
  ]
}



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