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CVE-2023-36845

Juniper Junos OS EX Series and SRX Series PHP External Variable Modification

9.8 CRITICALActively exploited (CISA KEV)Public exploitEPSS 95.1%
  1. Published17 Aug 2023
  2. Added to CISA KEV13 Nov 2023
  3. Remediation due17 Nov 2023
Actively exploited (CISA KEV)

Juniper Junos OS on EX Series and SRX Series contains a PHP external variable modification vulnerability that allows an unauthenticated, network-based attacker to control an important environment variable. Using a crafted request, which sets the variable PHPRC, an attacker is able to modify the PHP execution environment allowing the injection und execution of code.

Added to KEV: 13 Nov 2023Federal remediation due: 17 Nov 2023

Description

A PHP External Variable Modification vulnerability in J-Web of Juniper Networks Junos OS on EX Series and SRX Series allows an unauthenticated, network-based attacker to remotely execute code. Using a crafted request which sets the variable PHPRC an attacker is able to modify the PHP execution environment allowing the injection und execution of code. This issue affects Juniper Networks Junos OS on EX Series and SRX Series: * All versions prior to 20.4R3-S9; * 21.1 versions 21.1R1 and later; * 21.2 versions prior to 21.2R3-S7; * 21.3 versions prior to 21.3R3-S5; * 21.4 versions prior to 21.4R3-S5; * 22.1 versions prior to 22.1R3-S4; * 22.2 versions prior to 22.2R3-S2; * 22.3 versions prior to 22.3R2-S2, 22.3R3-S1; * 22.4 versions prior to 22.4R2-S1, 22.4R3; * 23.2 versions prior to 23.2R1-S1, 23.2R2.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Juniper Junos< 20.4 · 20.4 · 21.1 · 21.2

Remediation

Fixed in
Juniper Junos≥ 20.4

References

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Frequently asked

Is CVE-2023-36845 being actively exploited?

Yes. CVE-2023-36845 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 13 Nov 2023.

How severe is CVE-2023-36845?

CVE-2023-36845 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 95.1% probability of exploitation.

Which products are affected by CVE-2023-36845?

Affected products include Juniper Junos.

How do I fix CVE-2023-36845?

Upgrade affected software to a fixed version, for example Juniper Junos 20.4 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2023-36845 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, a risk for it never ranks below high, and the update that fixes it moves to the Emergency patch lane. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.