CVE-2026-48487: Zeroconf is a pure Python implementation of multicast DNS service discovery

Routine

MEDIUM 5.3REMOTEUPGRADE

CVE-2026-48487 is a medium-severity flaw (CVSS 5.3) affecting zeroconf. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 60%)
CISA exploited list	No
Weakness	CWE-130
Published	2026-07-17
Last modified	2026-08-17

Publisher (CNA): GitHub, Inc. · Vendor: paulsm

Last updated 2026-08-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-17 19:17 UTCPublished CVE record published
2026-08-17 20:06 UTCUpdated Record last modified

paulsm zeroconf UPGRADE

Affected: < 0.149.16

Fixed in: 0.149.16

Safe to downgrade to: no unaffected older release

1. Check installed version

pip show zeroconf

2. UPGRADE to 0.149.16

pip install --upgrade "zeroconf>=0.149.16"

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-48487?

zeroconf: upgrade to 0.149.16. Exact commands for each OS are on this page.

Is CVE-2026-48487 being exploited?

CVE-2026-48487 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-48487 affect?

CVE-2026-48487 affects zeroconf. Severity is medium (CVSS 5.3). 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 checkin

How urgent is CVE-2026-48487?

Priority 34/100. Remotely exploitable, no login, no user action

Software pages

Python vulnerabilities

Related CVEs

CVE-2026-48045 MEDIUM 6.5 UPGRADE Zeroconf is a pure Python implementation of multicast DNS service discovery
CVE-2026-47184 MEDIUM 6.5 UPGRADE Zeroconf is a pure Python implementation of multicast DNS service discovery
CVE-2026-47183 MEDIUM 6.5 UPGRADE Zeroconf is a pure Python implementation of multicast DNS service discovery
CVE-2026-47180 MEDIUM 6.5 UPGRADE Zeroconf is a pure Python implementation of multicast DNS service discovery

References

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