Is CVE-2026-21906 in the CISA KEV catalog?

No. CVE-2026-21906 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-21906?

CVE-2026-21906 has a CVSS v3 base score of 7.5 (HIGH).

What is the EPSS score for CVE-2026-21906?

CVE-2026-21906 has an EPSS score of 0.50% (39th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2026-21906

HIGH

7.5

CVSS v3

NVD

Description

An Improper Handling of Exceptional Conditions vulnerability in the packet forwarding engine (PFE) of Juniper Networks Junos OS on SRX Series allows an unauthenticated network-based attacker sending a specific ICMP packet through a GRE tunnel to cause the PFE to crash and restart. When PowerMode IPsec (PMI) and GRE performance acceleration are enabled and the device receives a specific ICMP packet, a crash occurs in the SRX PFE, resulting in traffic loss. PMI is enabled by default, and GRE performance acceleration can be enabled by running the configuration command shown below. PMI is a mode of operation that provides IPsec performance improvements using Vector Packet Processing. Note that PMI with GRE performance acceleration is only supported on specific SRX platforms. This issue affects Junos OS on the SRX Series: * all versions before 21.4R3-S12, * from 22.4 before 22.4R3-S8, * from 23.2 before 23.2R2-S5, * from 23.4 before 23.4R2-S5, * from 24.2 before 24.2R2-S3, * from 24.4 before 24.4R2-S1, * from 25.2 before 25.2R1-S1, 25.2R2.

CWE-755

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploit Intelligence

0.50%probability of exploitation in 30 days

39thpercentile

Low risk: more likely to be exploited than 39% of all known CVEs.

References

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-01-23.