CVE-2026-21906
Unauthenticated ICMP via GRE with PMI crashes SRX PFE, causing traffic loss.
Is CVE-2026-21906 being exploited?
Not confirmed. CVE-2026-21906 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.55% probability of exploitation in the next 30 days.
How severe is CVE-2026-21906?
CVE-2026-21906 is rated High with a CVSS score of 8.7. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-21906?
Yes. A fix has been recorded for CVE-2026-21906. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-21906 affect?
CVE-2026-21906 affects Juniper Junos OS SRX Series, PMI-enabled with GRE acceleration (specific versions). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-21906?
Plan patch ASAP when updates are released
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote PFE crash on SRX Series; PMI + GRE acceleration enabled; traffic disruption.
Patch when available
- affected< 21.4R3-S12
- affected>= 22.4 and < 22.4R3-S8
- affected>= 23.2 and < 23.2R2-S5
- affected>= 23.4 and < 23.4R2-S5
- affected>= 24.2 and < 24.2R2-S3
- affected>= 24.4 and < 24.4R2-S1
- affected>= 25.2 and < 25.2R1-S1, 25.2R2
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.