CVE-2026-57026
Malformed SIP INVITE can crash Junos flowd, causing device/service outage.
Is CVE-2026-57026 being exploited?
Not confirmed. CVE-2026-57026 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 0.46% probability of exploitation in the next 30 days.
How severe is CVE-2026-57026?
CVE-2026-57026 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-2026-57026?
Yes. A fix has been recorded for CVE-2026-57026. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-57026 affect?
CVE-2026-57026 affects Juniper Junos OS on MX Series (SPC3), Juniper SRX Series, Affected versions: all before 23.2R2-S7, 23.4 before 23.4R2-S8, 24.2 before 24.2R2-S5, 24.4 before 24.4R2-S4, 25.2 before 25.2R2, 25.4 before 25.4R1-S2. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-57026?
Apply Juniper patches immediately; if needed, disable SIP ALG and block untrusted SIP traffic.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Unauthenticated network attacker can send a malformed SIP INVITE that crashes flowd via SIP ALG, causing complete device/service DoS.
Immediate action required
- affected< 23.2R2-S7
- affected>= 23.4 and < 23.4R2-S8
- affected>= 24.2 and < 24.2R2-S5
- affected>= 24.4 and < 24.4R2-S4
- affected>= 25.2 and < 25.2R2
- affected>= 25.4 and < 25.4R1-S2
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.