CVE-2026-57020: An Improper Check for Unusual or Exceptional Conditions vulnerability in the packet forwarding engine (pfe) of Juniper Networks Junos OS on QFX10000 Series allows an unauthenticate

mediumCVSS 6.5CVE-2026-57020

An Improper Check for Unusual or Exceptional Conditions vulnerability in the packet forwarding engine (pfe) of Juniper Networks Junos OS on QFX10000 Series allows an unauthenticated, adjacent attacker to cause a Denial-of-Service (DoS). On all QFX10000 platforms in an EVPN-VxLAN scenario, if an attacker sends IPv6 multicast traffic and these packets reach the non-IRB interface of a spine switch it floods the packet to other spines and all Ethernet Segment Identifier (ESI) leaf switches. This flooding causes the packet to be forwarded in a endless loop, which can lead to saturation of the involved links and in turn impact to legitimate traffic. This issue affects Junos OS on QFX10000 Series: - all versions before 23.2R2-S7, - 23.4 versions before 23.4R2-S8, - 24.2 versions before 24.2R2-S4, - 24.4 versions before 24.4R2-S4. This issue does not affect Junos version after 24.4 as the QFX10000 Series devices are not supported on newer versions anymore.

Details

Source: NVD Recent CVEs (US · database · site)
Severity: medium — CVSS 6.5
Published: 2026-07-09
Last updated: 2026-07-10
Exploitation: Not in CISA KEV at last sync

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-57020

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-570200.27% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 19% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-57020	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

high[NEW] [high] Juniper JUNOS and JUNOS Evolved: Multiple vulnerabilitiescert-bund
unknownJuniper Junos OS Multiple Vulnerabilitieshkcert
unknownMultiple vulnerabilities in Juniper Networks products (July 09, 2026)cert-fr-avis

Recent advisories for An Improper Check

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

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