CVE-2025-59529: Avahi is a system which facilitates service discovery on a local network via the mDNS/DNS-SD protocol suite

Q: How do I fix CVE-2025-59529?

avahi: upgrade to 0.9. Exact commands for each OS are on this page.

Q: Is CVE-2025-59529 being exploited?

CVE-2025-59529 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2025-59529 affect?

CVE-2025-59529 affects avahi. Severity is medium (CVSS 5.5). Avahi is a system which facilitates service discovery on a local network via the mDNS/DNS-SD protocol suite. In versions up to and including 0.9-rc5, the simple protocol server ignores the documented client limit and accepts unlimited conne

Q: How urgent is CVE-2025-59529?

Priority 26/100. Public exploit reference

Routine

MEDIUM 5.5UPGRADE

CVE-2025-59529 is a medium-severity flaw (CVSS 5.5) affecting avahi. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Avahi is a system which facilitates service discovery on a local network via the mDNS/DNS-SD protocol suite. In versions up to and including 0.9-rc5, the simple protocol server ignores the documented client limit and accepts unlimited connections, allowing for easy local DoS. Although `CLIENTS_MAX` is defined, `server_work()` unconditionally `accept()`s and `client_new()` always appends the new client and increments `n_clients`. There is no check

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.2% (top 93%)
CISA exploited list	No
Weakness	CWE-400
Published	2025-12-18
Last modified	2026-10-23

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

Am I affected?

Timeline

2025-12-18 21:15 UTCPublished CVE record published
2026-10-23 20:17 UTCUpdated Record last modified

avahi avahi UPGRADE

Affected: < 0.9 · 0.9 rc1

Fixed in: 0.9

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy avahi || rpm -q avahi || avahi --version

2. UPGRADE to 0.9 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade avahi

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade avahi

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

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-2025-59529?

avahi: upgrade to 0.9. Exact commands for each OS are on this page.

Is CVE-2025-59529 being exploited?

CVE-2025-59529 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-2025-59529 affect?

CVE-2025-59529 affects avahi. Severity is medium (CVSS 5.5). Avahi is a system which facilitates service discovery on a local network via the mDNS/DNS-SD protocol suite. In versions up to and including 0.9-rc5, the simple protocol server ignores the documented client limit and accepts unlimited conne

How urgent is CVE-2025-59529?

Priority 26/100. Public exploit reference

Related CVEs

CVE-2026-24401 MEDIUM 6.5 UPGRADE Avahi is a system which facilitates service discovery on a local network via the mDNS/DNS-SD protocol suite

References

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