CVE-2026-33797
Junos OS and Junos OS Evolved: An attacker sending a specific genuine BGP packet causes a BGP reset
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 does not affect Junos OS versions before 25.2R1.
This issue affects Junos OS Evolved:
- 25.2-EVO versions before 25.2R2-EVO
This issue does not affect Junos OS Evolved versions before 25.2R1-EVO.
eBGP and iBGP are affected. IPv4 and IPv6 are affected.
Attack profile
How easy it is to exploit
- Attack vector
- Adjacent network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Junos OS and Junos OS Evolved: An attacker sending a specific genuine BGP packet causes a BGP reset
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 does not affect Junos OS versions before 25.2R1.
This issue affects Junos OS Evolved:
- 25.2-EVO versions before 25.2R2-EVO
This issue does not affect Junos OS Evolved versions before 25.2R1-EVO.
eBGP and iBGP are affected. IPv4 and IPv6 are affected.
- Record
CVE-2026-33797- CVSS 4.0
- 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/R:A/V:C/RE:M/U:Green - CVSS 3.1
- 7.4 High
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H - Weakness
- CWE-20
- Updated
- 2026-11-02
EUVDEUVD-2026-21208
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 does not affect Junos OS versions before 25.2R1.
This issue affects Junos OS Evolved:
- 25.2-EVO versions before 25.2R2-EVO
This issue does not affect Junos OS Evolved versions before 25.2R1-EVO.
eBGP and iBGP are affected. IPv4 and IPv6 are affected.
- Record
EUVD-2026-21208- CVSS 4.0
- 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/R:A/V:C/RE:M/U:Green - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-3rpc-j6fw-646r
An Improper Input Validation vulnerability in Juniper Networks Junos OS and Junos OS Evolved...
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.
- Record
GHSA-3rpc-j6fw-646r- CVSS 4.0
- 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/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 3.1
- 7.4 High
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H - Weakness
- CWE-20
- Updated
- 2026-11-02
NVD
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 does not affect Junos OS versions before 25.2R1.
This issue affects Junos OS Evolved:
- 25.2-EVO versions before 25.2R2-EVO
This issue does not affect Junos OS Evolved versions before 25.2R1-EVO.
eBGP and iBGP are affected. IPv4 and IPv6 are affected.
- Record
CVE-2026-33797- CVSS 4.0
- 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/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 3.1
- 7.4 High
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H - Weakness
- CWE-20
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-33797 is a high vulnerability (CVSS 7.1) in Juniper Junos, published April 9, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.17%, the 5th percentile. No source names a fixed version.