CVE-2021-0251
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Junos OS: MX Series with MS-PIC, MS-SPC3, MS-MIC or MS-MPC: The BRAS Subscriber Services service activation portal is vulnerable to a Denial of Service (DoS) via malformed HTTP packets
rank 21 = 0 + 13 + 0 + 8 + 0
rank@v1 · backlog
Someone is already using it
CISA KEV catalog · public proof-of-concept · FIRST EPSS
EPSS 0.01064 · without this subject the record ranks 21
What it costs you if it fires
NVD CVSS base score, then the CNA's own
CVSS 5.0, from NVD · without this subject the record ranks 8
It is getting worse, not staying still
FIRST EPSS series, rescorings and bad loads removed
no persisting rise in 365 days · without this subject the record ranks 21
How much of the world it touches
NVD CPE configurations
9 products in the CPE ranges · without this subject the record ranks 13
Someone else already set the date
CISA KEV remediation due date
no CISA due date · without this subject the record ranks 21
$32,500 = $4.99M incident cost x 0.6121449559255632 exposure x 0.01064 likelihood
udv@v1 · unaudited · wrong for you until you say what you run
$4.99M is the cost of a breach that happened, from IBM Cost of a Data Breach Report 2026, global average. It is not the value of any asset of yours. That average already covers breaches of every severity, so scaling it by exposure understates a partial-impact record. That is an assumption, not a measurement. Your own asset value goes in the decision record.
Hindsight · the state
Foresight · where to check next
No weakness class or product neighbourhood is held for this record, so this index cannot name anywhere to check next. That is an absence in the record, not a finding about the software.
Sources disagree here.
Both shown, dated. We don't pick winners. disagreement-rules@v1
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Harm, if it fires from the vector and the weakness
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CISA KEV & Federal Remediation Deadline from the record and CISA
The fix, and how long it's been waiting.
Exploit Status & Known PoCs a ladder, not a score
Current rung: Nothing observed in held sources.
- RUNG 1Nothing observed in held sources
- RUNG 2Proof-of-concept published
- RUNG 3Exploited in the wild · CISA KEV listed
- RUNG 4Ransomware campaign use known
Affected & Fixed Versions as published
Show all 9 published ranges
A rung lights from a row in the index, never from an assessment. "Held sources" is the true scope of the claim: this index reads the CVE record, NVD, CISA KEV, FIRST's EPSS and public proof-of-concept repositories, and it does not observe attacks.
Attack path
What it is stated by the CNA
A NULL Pointer Dereference vulnerability in the Captive Portal Content Delivery (CPCD) services daemon (cpcd) of Juniper Networks Junos OS on MX Series with MS-PIC, MS-SPC3, MS-MIC or MS-MPC allows an attacker to send malformed HTTP packets to the device thereby causing a Denial of Service (DoS), crashing the Multiservices PIC Management Daemon (mspmand) process thereby denying users the ability to login, while concurrently impacting other mspmand services and traffic through the device. Continued receipt and processing of these malformed packets will create a sustained Denial of Service (DoS) condition. receipt
Read the rest of the CNA's description
While the Services PIC is restarting, all PIC services will be bypassed until the Services PIC completes its boot process. An attacker sending these malformed HTTP packets to the device who is not part of the Captive Portal experience is not able to exploit this issue. This issue is not applicable to MX RE-based CPCD platforms. This issue affects: Juniper Networks Junos OS on MX Series 17.3 version 17.3R1 and later versions prior to 17.4 versions 17.4R2-S9, 17.4R3-S2; 18.1 versions prior to 18.1R3-S9; 18.2 versions prior to 18.2R3-S3; 18.3 versions prior to 18.3R3-S1; 18.4 versions prior to 18.4R3; 19.1 versions prior to 19.1R2-S2, 19.1R3; 19.2 versions prior to 19.2R2; 19.3 versions prior to 19.3R3. This issue does not affect: Juniper Networks Junos OS versions prior to 17.3R1.
NVD's analysis a second authority
- severity
- 5 AV:N/AC:L/Au:N/C:N/I:N/A:P
- weakness
- CWE-476
- affected versions
- juniper junos 17.3; juniper junos 17.4; juniper junos 18.1; and 6 more, listed in full below
- also scored by
- [email protected] 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
The CNA scored it 8.6 and NVD 5. Both are shown because both were published; we do not pick one.
check it yourself kb.juniper.net receipt
Movement the material steps
Show all 13 observations
13 observations held. A highlighted step crossed a promotion threshold. A step marked with a scoring model moved because the instrument was replaced, not because the vulnerability changed. receipt
The full biography
The record had been public for 5 years, 1 month when this index was last written.
Siblings and hubs
Records related to this one
No record cites this identifier and it carries no alias. Its defect family is below.
Its defect family
juniper networks junos os
Of the 14 records in this family, this is the only one holding a stated fix version: 17.3R1; 17.4R2-S9, 17.4R3-S2; 18.1R3-S9; 18.2R3-S3; 18.3R3-S.
Grouped by shared product and weakness, not by shared vulnerability. Each record's own state is on its own page.
Family membership: computed, pro@dim2000
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What usually comes next
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