Medium 5.3Published Jul 17, 2026

CVE-2026-48487Zeroconf: Unvalidated rdlength in record payload readers allows LAN-local cache corruption via crafted mDNS packet

Updated under an hour ago (Oct 26, 2026, 8:23 AM ET)

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No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

Zeroconf is a pure Python implementation of multicast DNS service discovery. Prior to 0.149.16, _read_character_string and _read_string in src/zeroconf/_protocol/incoming.py advanced self.offset by attacker-declared RDLENGTH without checking it against self._data_len, allowing unauthenticated hosts on the local link over UDP/5353 (224.0.0.251 / ff02::fb) to send a TXT, HINFO, or A/AAAA record with rdlength=65535 and seed DNSCache and ServiceInfo.properties with truncated, attacker-shaped key/value or address records. This issue is fixed in version 0.149.16.

CVSS: 5.3 MEDIUM (v4.0, CNA)CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
Weakness (CWE): CWE-130
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Jul 20, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

python-zeroconf python-zeroconf python_zeroconf:python_zeroconf (from the name)	before 0.149.16	CNA record
paulsm zeroconf paulsm:zeroconf	before 0.149.16	NVD

References

https://github.com/python-zeroconf/python-zeroconf/security/advisories/GHSA-qc2x-6f54-m6h9x-refsource-confirm, vendor-advisory
https://github.com/python-zeroconf/python-zeroconf/issues/1752x-refsource-misc, issue-tracking, patch
https://github.com/python-zeroconf/python-zeroconf/pull/1756x-refsource-misc, issue-tracking, patch
https://github.com/python-zeroconf/python-zeroconf/commit/544449596e645fcaad3834fa0cb614a54f847a82x-refsource-misc, patch
https://github.com/python-zeroconf/python-zeroconf/releases/tag/0.149.16x-refsource-misc, release-notes

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.