CVE-2021-31354
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Junos OS and Junos OS Evolved: A vulnerability in the Juniper Agile License Client may allow an attacker to perform Remote Code Execution (RCE)
rank 31 = 0 + 22 + 0 + 9 + 0
rank@v1 · scheduled
Someone is already using it
CISA KEV catalog · public proof-of-concept · FIRST EPSS
EPSS 0.00629 · without this subject the record ranks 31
What it costs you if it fires
NVD CVSS base score, then the CNA's own
CVSS 8.8, from NVD · without this subject the record ranks 9
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 31
How much of the world it touches
NVD CPE configurations
13 products in the CPE ranges · without this subject the record ranks 22
Someone else already set the date
CISA KEV remediation due date
no CISA due date · without this subject the record ranks 31
$29,100 = $4.99M incident cost x 0.9280467328949208 exposure x 0.00629 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
This record is one instance of CWE-125, out-of-bounds read. The index holds 9767 prior instances of this class, 19 KEV-listed. The nearest of its KEV-listed records are drawn beside this. taxonomy@v1
Sources disagree here.
Both shown, dated. We don't pick winners. disagreement-rules@v1
Running Juniper Networks Junos OS? Check your version
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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 13 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
An Out Of Bounds (OOB) access vulnerability in the handling of responses by a Juniper Agile License (JAL) Client in Juniper Networks Junos OS and Junos OS Evolved, configured in Network Mode (to use Juniper Agile License Manager) may allow an attacker to cause a partial Denial of Service (DoS), or lead to remote code execution (RCE). The vulnerability exists in the packet parsing logic on the client that processes the response from the server using a custom protocol. receipt
Read the rest of the CNA's description
An attacker with control of a JAL License Manager, or with access to the local broadcast domain, may be able to spoof a new JAL License Manager and/or craft a response to the Junos OS License Client, leading to exploitation of this vulnerability. This issue only affects Junos systems configured in Network Mode. Systems that are configured in Standalone Mode (the default mode of operation for all systems) are not vulnerable to this issue. This issue affects: Juniper Networks Junos OS: 19.2 versions prior to 19.2R3-S3; 19.3 versions prior to 19.3R3-S3; 20.1 versions prior to 20.1R2-S2, 20.1R3-S1; 20.2 versions prior to 20.2R3-S2; 20.3 versions prior to 20.3R3; 20.4 versions prior to 20.4R3; 21.1 versions prior to 21.1R2. Juniper Networks Junos OS Evolved: version 20.1R1-EVO and later versions, prior to 21.2R2-EVO. This issue does not affect Juniper Networks Junos OS versions prior to 19.2R1.
NVD's analysis a second authority
- severity
- 8.8 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- weakness
- CWE-125
- affected versions
- juniper junos 19.2; juniper junos 19.3; juniper junos 20.1; and 10 more, listed in full below
- also scored by
- [email protected] 7.1 CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L
The CNA scored it 7.1 and NVD 8.8. 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 29 observations
29 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 4 years, 9 months when this index was last written.
The pattern, elsewhere
This record is one instance of CWE-125, out-of-bounds read. The index holds 9767 prior instances of this class, 19 KEV-listed. The nearest of its KEV-listed records are drawn beside this. [email protected]
"Matches n of m" counts the attributes the two records can both be compared on: the CVSS metrics they share a version of, any weakness class beyond this one, and the vendor. fit-rules@v1
9767 records in this class held. The six above are drawn from the ones CISA has listed as exploited, ranked by how much of the record matches this one. That is why every one of them is KEV-listed: the pool is, so the colour on those spokes says nothing the pool has not already said.
No curated product neighbourhood is held for this product, so the records above are the nearest this index can name. The neighbourhood table covers a small set of products and is extended by hand.
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 8 records in this family, this is the only one holding a stated fix version: 19.2R1; 19.2R3-S3; 19.3R3-S3; 20.1R2-S2, 20.1R3-S1; 20.2R3-S.
Grouped by shared product and weakness, not by shared vulnerability. Each record's own state is on its own page.
Family membership: held values
This record is one of a group, and the group's page describes all of them. This page is kept and dated, and the defect family's own page is the one we offer for indexing: the whole group.
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What usually comes next
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