Is CVE-2026-21917 in the CISA KEV catalog?

No. CVE-2026-21917 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-21917?

CVE-2026-21917 has a CVSS v3 base score of 7.5 (HIGH).

What is the EPSS score for CVE-2026-21917?

CVE-2026-21917 has an EPSS score of 0.38% (29th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2026-21917

HIGH

7.5

CVSS v3

NVD

Description

An Improper Validation of Syntactic Correctness of Input vulnerability in the Web-Filtering module of Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS). If an SRX device configured for UTM Web-Filtering receives a specifically malformed SSL packet, this will cause an FPC crash and restart. This issue affects Junos OS on SRX Series: * 23.2 versions from 23.2R2-S2 before 23.2R2-S5, * 23.4 versions from 23.4R2-S1 before 23.4R2-S5, * 24.2 versions before 24.2R2-S2, * 24.4 versions before 24.4R1-S3, 24.4R2. Earlier versions of Junos are also affected, but no fix is available.

CWE-1286

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

0.38%probability of exploitation in 30 days

29thpercentile

Low risk: more likely to be exploited than 29% 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.