CVE-2023-36845 Juniper Junos OS: software flaw
In plain words: A mistake in the software that attackers have found a way to abuse. Depends on the product — see the description and the vendor advisory.
Confirmed exploited by CISA on · US federal patch deadline Nov 17, 2023
What to do
- Install Juniper's security update for Junos OS. If no update exists, follow the vendor's workaround or stop using the product until one ships.
- Patch edge devices first — attackers often start scanning for them within hours of a fix.
- Never expose the device's admin page to the internet.
- After patching a device that was exposed, follow the vendor's compromise checks, end active sessions and change passwords.
Who is affected
Work IT. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.
What's at risk: They face the internet and guard the whole network, so a flaw here can hand attackers a way in — and these devices usually run no antivirus, so break-ins go unnoticed.
The details
- Official name
- Juniper Junos OS EX Series and SRX Series PHP External Variable Modification Vulnerability
- Product
- Juniper Junos OS
- CISA description
- 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.
- Type of flaw
- Software flaw (CWE-473)
- Confirmed exploited
- Nov 13, 2023
- US federal patch deadline
- Nov 17, 2023
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Answering about CVE-2023-36845 ·
Questions about CVE-2023-36845
Is CVE-2023-36845 being exploited?
Yes. CISA added CVE-2023-36845 to its Known Exploited Vulnerabilities catalog on Nov 13, 2023, which means there is reliable evidence of real-world attacks.
How do I fix CVE-2023-36845?
Install Juniper's security update for Junos OS. If no update exists, follow the vendor's workaround or stop using the product until one ships. Patch edge devices first — attackers often start scanning for them within hours of a fix.
Am I affected by CVE-2023-36845?
Only if you use Juniper Junos OS. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.