CVE-2026-21903
published 2026-01-15CVE-2026-21903: A Stack-based Buffer Overflow vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS allows a network-based attacker, authenticated…
PriorityP340medium6.5CVSS 3.1
AVNACLPRLUINSUCNINAH
EPSS
0.36%
28.2th percentile
A Stack-based Buffer Overflow vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS allows a network-based attacker, authenticated with low privileges to cause a Denial-of-Service (DoS).
Subscribing to telemetry sensors at scale causes all FPC connections to drop, resulting in an FPC crash and restart.
The issue was not seen when YANG packages for the specific sensors were installed.
This issue affects Junos OS:
* all versions before 22.4R3-S7,
* 23.2 version before 23.2R2-S4,
* 23.4 versions before 23.4R2.
Affected
8 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| juniper | junos | < 22.4 | 22.4 |
| juniper | junos | — | — |
| juniper | junos | — | — |
| juniper | junos | — | — |
| juniper | junos_os | — | — |
| juniper_networks | junos_os | < 22.4R3-S7 | 22.4R3-S7 |
| juniper_networks | junos_os | >= 23.2 < 23.2R2-S4 | 23.2R2-S4 |
| juniper_networks | junos_os | >= 23.4 < 23.4R2 | 23.4R2 |
CVSS provenance
nvdv3.16.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
nvdv4.07.1HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:L/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:X/R:X/V:X/RE:X/U:X
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GHSA
GHSA-h3c8-3472-7v7g: A Stack-based Buffer Overflow vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS allows a network-based attacker, authen
ghsa_unreviewed·2026-01-15
CVE-2026-21903 [HIGH] CWE-121 GHSA-h3c8-3472-7v7g: A Stack-based Buffer Overflow vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS allows a network-based attacker, authen
A Stack-based Buffer Overflow vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS allows a network-based attacker, authenticated with low privileges to cause a Denial-of-Service (DoS).
Subscribing to telemetry sensors at scale causes all FPC connections to drop, resulting in an FPC crash and restart.
The issue was not seen when YANG packages for the specific sensors were installed.
This issue affects Junos OS:
* all versions before 22.4R3-S7,
* 23.2 version before 23.2R2-S4,
* 23.4 versions before 23.4R2.
Juniper
CVE-2026-21903: A Stack-based Buffer Overflow vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS allows a network-based attacker, authen
vendor_juniper·2026-01-15·CVSS 6.5
CVE-2026-21903 [MEDIUM] CWE-121 CVE-2026-21903: A Stack-based Buffer Overflow vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS allows a network-based attacker, authen
CVE-2026-21903: A Stack-based Buffer Overflow vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS allows a network-based attacker, authenticated with low privileges to cause a Denial-of-Service (DoS).
Subscribing to telemetry sensors at scale causes all FPC connections to drop, resulting in an FPC crash and restart.
The issue was not seen when YANG packages for the specific sensors were installed.
This issue affects Junos OS:
* all versions before 22.4R3-S7,
* 23.2 version before 23.2R2-S4,
* 23.4 versions before 23.4R2.
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
2026-01-15
Published