Zeroconf is a pure Python implementation of multicast DNS service discovery. Prior to 0.149.6, DNSIncoming._log_exception_debug and the four QuietLogger exception-dedup methods stored an unbounded _seen_logs dictionary keyed by attacker-influenced IncomingDecodeError messages, retaining sys.exc_info() tracebacks whose frame locals kept raw packet self.data buffers and allowing unauthenticated hosts on the local link over UDP/5353 (224.0.0.251 / ff02::fb) to drive memory growth until mDNS-dependent features degrade or the process is OOM-killed. This issue is fixed in version 0.149.6.
CVE-2026-47183
MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreMEDIUM confidence
This medium-severity CVE scores 6.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 85% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: epss, secondary
6.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 6.5Exploit: NoneExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 6.5
- EG Score
- 6.5(medium)
- EG Risk
- 29(Track)EG Risk 29/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity65% × 45%Exploitation0% × 40%Automatability0% × 15%Action: Routine — remediate on your standard cadence. - EPSS
- 15.4%
- KEV
- Not listed
Published
May 29, 2026
Last Modified
July 18, 2026
Advisory Details (5)
Auto-updated Jul 17, 2026Patch available. Sources: github_commit, github_pr, github_release, github.
github Patch Available
Unbounded exception-dedup state retains packet buffers via traceback frame locals, enabling LAN-local memory exhaustion · Advisory · python-zeroconf/python-zeroconf · GitHub
https://github.com/python-zeroconf/python-zeroconf/security/advisories/GHSA-phvx-9mgw-67r5github_release Patch Available
0.149.6
Patch available: python-zeroconf/python-zeroconf 0.149.6
https://github.com/python-zeroconf/python-zeroconf/releases/tag/0.149.6github_pr Patch Available
fix: bound _seen_logs and stop retaining exc_info
Patch available: python-zeroconf/python-zeroconf 0.149.6 (PR #1717 merged 2026-05-18)
https://github.com/python-zeroconf/python-zeroconf/pull/1717generic
Security: Unbounded `_seen_logs` module dict retains tracebacks (and packet bytes) for every unique decode error · Issue #1714 · python-zeroconf/python-zeroconf · GitHub
https://github.com/python-zeroconf/python-zeroconf/issues/1714github_commit Patch Available
commit 95561e28b249 (python-zeroconf/python-zeroconf)
Patch available: python-zeroconf/python-zeroconf 0.149.6 (contains commit 95561e28b249)
https://github.com/python-zeroconf/python-zeroconf/commit/95561e28b24922358f1991e38e3a86d70d72dcecVendor Advisories for CVE-2026-47183(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Affected Packages
(1 across 1 ecosystem)
PyPI(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| zeroconf | 0.100.0 ... 0.99.0 (252 versions) | 0.149.6 | — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 6× in last 7d / 6× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-23 03:17 UTCEG score recompute
- 2026-07-22 14:08 UTCEPSS rescore
- 2026-07-21 15:24 UTCEPSS rescore
- 2026-07-20 17:08 UTCEPSS rescore
- 2026-07-19 14:31 UTCEPSS rescore
- 2026-07-19 02:29 UTCEPSS rescore
- 2026-06-14 23:18 UTCEPSS rescore
- 2026-06-13 23:00 UTCEPSS rescore
- 2026-06-12 23:12 UTCEPSS rescore
- 2026-05-29 20:20 UTCEG score recompute
Related CVEs(same CWE)
Same CWE
10 shownCWE-400
Frequently asked(5)
What is CVE-2026-47183?
CVE-2026-47183 is a medium vulnerability published on May 29, 2026. Zeroconf is a pure Python implementation of multicast DNS service discovery. Prior to 0.149.6, DNSIncoming.logexceptiondebug and the four QuietLogger exception-dedup methods stored an unbounded seenlogs dictionary keyed by attacker-influenced IncomingDecodeError messages, retaining sys.excinfo()…
When was CVE-2026-47183 disclosed?
CVE-2026-47183 was first published in the National Vulnerability Database on May 29, 2026, with the most recent update on July 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-47183 actively exploited?
CVE-2026-47183 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 15.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-47183?
CVE-2026-47183 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-47183?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-47183, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-47183
Is Your Infrastructure Affected by CVE-2026-47183?
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