Junos OS and Junos OS Evolved: An attacker sending a specific genuine BGP packet causes a BGP reset
Summary
| CVE | CVE-2026-33797 |
|---|---|
| State | PUBLISHED |
| Assigner | juniper |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-04-09 22:16:29 UTC |
| Updated | 2026-04-09 22:16:29 UTC |
| Description | An Improper Input Validation vulnerability in Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, adjacent attacker, sending a specific genuine BGP packet in an already established BGP session to reset only that session causing a Denial of Service (DoS). An attacker repeatedly sending the packet will sustain the Denial of Service (DoS).This issue affects Junos OS: * 25.2 versions before 25.2R2 This issue doesn't not affected Junos OS versions before 25.2R1. This issue affects Junos OS Evolved: * 25.2-EVO versions before 25.2R2-EVO This issue doesn't not affected Junos OS Evolved versions before 25.2R1-EVO. eBGP and iBGP are affected. IPv4 and IPv6 are affected. |
Risk And Classification
Primary CVSS: v4.0 7.1 HIGH from [email protected]
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:A/V:C/RE:M/U:Green
EPSS: 0.000220000 probability, percentile 0.059740000 (date 2026-04-10)
Problem Types: CWE-20 | CWE-20 CWE-20 Improper Input Validation
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 7.1 | HIGH | CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/C... |
| 4.0 | CNA | CVSS | 7.1 | HIGH | CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/... |
| 3.1 | [email protected] | Primary | 7.4 | HIGH | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H |
| 3.1 | CNA | CVSS | 7.4 | HIGH | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H |
CVSS v4.0 Breakdown
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:A/V:C/RE:M/U:Green
CVSS v3.1 Breakdown
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Juniper Networks | Junos OS | affected 25.2 25.2R2 semver | Not specified |
| CNA | Juniper Networks | Junos OS | unaffected 25.2R1 semver | Not specified |
| CNA | Juniper Networks | Junos OS Evolved | affected 25.2 25.2R2-EVO semver | Not specified |
| CNA | Juniper Networks | Junos OS Evolved | unaffected 25.2R1-EVO semver | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| kb.juniper.net/JSA107850 | [email protected] | kb.juniper.net | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Additional Advisory Data
Solutions
CNA: The following software releases have been updated to resolve this specific issue: Junos OS: 25.2R2, 25.4R1, and all subsequent releases. Junos OS Evolved: 25.2R2-EVO, 25.4R1-EVO, and all subsequent releases.
Workarounds
CNA: There are no known workarounds for this issue.
Exploits
CNA: Juniper SIRT is not aware of any malicious exploitation of this vulnerability.