CVE-2026-33800— Junos OS: MX Series: In a VC scenario a high rate of micro-BFD session flaps will cause an FPC crash
Quick assessment
Affected
Juniper Networks Junos OS
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
Juniper Networks Junos OS是美国Juniper Networks公司的一款专为路由器、交换机和防火墙等物理及虚拟设备打造的网络操作系统。 Juniper Networks Junos OS存在输入验证错误漏洞，该漏洞源于Packet Forwarding Engine（pfe）存在未检查的循环条件输入漏洞，可能导致未经验证的相邻攻击者造成拒绝服务。以下版本受到影响：23.2R2-S7之前版本、23.4R2-S8之前版本的23.4版本、24.2R2-S4之前版本的24.2版本、24.
Possible ATT&CK Techniques 2 AI
T1498 · Network Denial of Service T1499 · Endpoint Denial of ServiceAffected Version Matrix 5
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| Juniper Networks | Junos OS | < 23.2R2-S7 |
affected |
23.4< 23.4R2-S8 |
affected | ||
24.2< 24.2R2-S4 |
affected | ||
24.4< 24.4R2-S3 |
affected | ||
25.2< 25.2R2 |
affected |
Get alerts for future matching vulnerabilities
Log in to subscribe
I. Basic Information for CVE-2026-33800
Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗
Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.
Vulnerability Title
Junos OS: MX Series: In a VC scenario a high rate of micro-BFD session flaps will cause an FPC crash
Source: CVE Program / CVE List V5
Vulnerability Description
An Unchecked Input for Loop Condition vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS on MX Series allows an unauthenticated, adjacent attacker to cause a Denial-of-Service (DoS).Micro-BFD session flaps generate respective up/down events which are queued by PFEMAN for processing. Especially in a Virtual-Chassis (VC) scenario with locality‑bias configured, processing takes a significant amount of time for each event. If these sessions keep flapping, new events are constantly added, and in turn PFEMAN never completes processing these events. This results in the PFEMAN watchdog timer expiring, which causes the FPC to crash and restart, representing a complete service outage.
This issue only affects MX series FPCs up to and including MPC9, and LC2101/2103 and LC480. It does not affect MPC10/11, LC4800/9600, and MX304.
This issue affects Junos OS on MX Series:
* all versions before 23.2R2-S7,
* 23.4 versions before 23.4R2-S8,
* 24.2 versions before 24.2R2-S4,
* 24.4 versions before 24.4R2-S3,
* 25.2 versions before 25.2R2.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
循环条件输入未经检查
Source: CVE Program / CVE List V5
Vulnerability Title
Juniper Networks Junos OS 输入验证错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Juniper Networks Junos OS是美国Juniper Networks公司的一款专为路由器、交换机和防火墙等物理及虚拟设备打造的网络操作系统。 Juniper Networks Junos OS存在输入验证错误漏洞，该漏洞源于Packet Forwarding Engine（pfe）存在未检查的循环条件输入漏洞，可能导致未经验证的相邻攻击者造成拒绝服务。以下版本受到影响：23.2R2-S7之前版本、23.4R2-S8之前版本的23.4版本、24.2R2-S4之前版本的24.2版本、24.
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| Juniper Networks | Junos OS | 0 ~ 23.2R2-S7 | - |
|
II. Public POCs for CVE-2026-33800
| # | POC Description | Source Link | Shenlong Link |
|---|
AI-Generated POC
Premium
No public POC found.
Login to generate AI POCIII. Intelligence Information for CVE-2026-33800
请登录查看更多情报信息。
Vendor Advisories for CVE-2026-33800 (1)
Same Patch Batch · Juniper Networks · 2026-07-09 · 22 CVEs total
| CVE-2026-57023 | 7.5 HIGH | Junos OS: MX with SPC3, SRX Series: A specifically malformed TCP packet causes a flowd cra |
| CVE-2026-57026 | 7.5 HIGH | Junos OS: MX Series with SPC3, SRX Series: Processing of a specifically malformed SIP invi |
| CVE-2026-57028 | 7.3 HIGH | Junos OS Evolved: A port which has been inadvertently exposed can be reached by an attacke |
| CVE-2026-57032 | 6.5 MEDIUM | Junos OS: EX Series: Subscribing to an unsupported telemetry sensor path causes fxpc proce |
| CVE-2026-33801 | 6.5 MEDIUM | Junos OS and Junos OS Evolved: When a specifically malformed BGP route update is received |
| CVE-2026-33803 | 6.5 MEDIUM | Junos OS Evolved: A port which has been inadvertently exposed can be reached by an attacke |
| CVE-2026-57019 | 6.5 MEDIUM | Junos OS: MX Series: Specific traffic causes an FPC to reset |
| CVE-2026-57020 | 6.5 MEDIUM | Junos OS: QFX10000 Series: IPv6 multicast traffic received on non-IRB interfaces causes a |
| CVE-2026-57027 | 6.5 MEDIUM | Junos OS: EX4100 Series, EX4400: With sFlow configured in a VC scenario multicast traffic |
| CVE-2026-57022 | 5.9 MEDIUM | Junos OS: MX Series with SPC3, SRX Series: Specific packet in response to a TCP connection |
| CVE-2026-57030 | 5.9 MEDIUM | Junos OS: SRX Series: Flow sessions are not getting cleared leading to a DoS |
| CVE-2026-33794 | 5.9 MEDIUM | Junos OS Evolved: PTX Series: Receipt of repeated ECMP routing updates results in PFE cras |
| CVE-2026-57054 | 5.8 MEDIUM | Junos OS: MX Series: Web filtering doesn't block specifically formatted URLs |
| CVE-2026-57025 | 5.5 MEDIUM | Junos OS and Junos OS Evolved: EX Series, QFX Series, MX Series: A specific 'show l2-learn |
| CVE-2026-33802 | 5.5 MEDIUM | Junos OS: EX Series: Unauthorized users can execute service-impacting CLI command |
| CVE-2026-57024 | 5.3 MEDIUM | Junos OS: MX with SPC3, SRX Series: Repeated VPN negotiation failures will eventually caus |
| CVE-2026-57021 | 5.3 MEDIUM | Junos OS: SRX Series: If VPN compliance-check is configured an attacker can cause http-gk |
| CVE-2026-57029 | 5.3 MEDIUM | Junos OS Evolved: QFX Series: When sFlow collector reachability changes evo-pfemand proces |
| CVE-2026-57031 | 4.7 MEDIUM | Junos OS: MX Series: For subscribers configured on static interfaces, input filters are no |
| CVE-2026-21901 | 4.4 MEDIUM | Junos OS and Junos OS Evolved: Configuration of a specific SSH option results in mgd crash |
Showing top 20 of 22 CVEs. View all on vendor page → →
IV. Related Vulnerabilities
Same product: Junos OS
-
CVE-2026-57054
Junos OS: MX Series: Web filtering doesn't block specificall -
CVE-2026-57032
Junos OS: EX Series: Subscribing to an unsupported telemetry -
CVE-2026-57031
Junos OS: MX Series: For subscribers configured on static in -
CVE-2026-57030
Junos OS: SRX Series: Flow sessions are not getting cleared -
CVE-2026-57027
Junos OS: EX4100 Series, EX4400: With sFlow configured in a
Same vendor: Juniper Networks
-
CVE-2026-57054
Junos OS: MX Series: Web filtering doesn't block specificall -
CVE-2026-57032
Junos OS: EX Series: Subscribing to an unsupported telemetry -
CVE-2026-57031
Junos OS: MX Series: For subscribers configured on static in -
CVE-2026-57030
Junos OS: SRX Series: Flow sessions are not getting cleared -
CVE-2026-57029
Junos OS Evolved: QFX Series: When sFlow collector reachabil
Same weakness: CWE-606
-
CVE-2026-16652
Temporal Server Schedule exclusion search can cause excessiv -
CVE-2026-93653
Poppler: poppler: unbounded cpu loop in splashoutputdev::til -
CVE-2026-85730
smol-toml: Denial of Service via malformed TOML documents -
CVE-2026-13761
Pega Platform versions 7.1.0 through 25.1.2 are affected by -
CVE-2026-16599
Denial of Service in GNU wget
V. Comments for CVE-2026-33800
No comments yet