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CVE-2023-36845

Junos OS: EX and SRX Series: A PHP vulnerability in J-Web allows an unauthenticated to control an important environment variable

Exploited in the wild. In CISA KEV since 2023‑11‑13. Fixed versions are out.

CVSS 3.19.8CriticalEPSS percentile99th95% chance in 30 daysCISA KEVListedsince 2023-11-13, due 2023-11-17
Public exploit: 3 sourcesFix2 products5 fixed builds listed below

Published Updated Sources: CVE.org, NVD, BDU

NVD CVE.org

What to do

Find your product and version, then upgrade to the build on the right.

  • Juniper Networks Junos OSAffected: < 20.4R3-S9Upgrade to: 20.4R3-S9Affected: ≥ 21.1, < 21.1*Upgrade to: 21.1*Affected: ≥ 21.2, < 21.2R3-S7Upgrade to: 21.2R3-S7Affected: ≥ 21.3, < 21.3R3-S5Upgrade to: 21.3R3-S5 + 9 more branchesStated by: CVE record
  • Juniper JunosAffected: < 20.4Upgrade to: 20.4Stated by: NVD

Versions as the sources state them. Full version matrix after sign-in

Check it yourselfA free Nuclei and OpenVAS check exists for this CVE. Run it against your hosts.Is your organisation exposed?Discuss checks for your systems with a specialist. Scope is agreed before testing.

Coverage timeline

0 publishers

  1. Added to CISA KEV catalog

    ·CISA KEV

Sourced from public security reporting — each date is when it was published, not when it happened.

What it is

From the CVE record

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.

In plain language

No plain-language summary for this CVE yet.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS99th
Public exploit
CISA KEV
CISA KEV

Listed as exploited in the wild since 2023-11-13.

US federal agencies must remediate by 2023-11-17.

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Public exploits

3 sources with a proof of concept or module.

Exploit links, PoCs and Metasploit modules after sign-in
EPSS

95% chance of exploitation activity in the next 30 days, which ranks it in the 99th percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

The patch came 133 days before any public exploit.

  1. OpenVAS check added
  2. Public exploit / PoCsource: packetstormnuclei check added
  3. Patch availableworkaround available, record updated
  4. Added to CISA KEV
  5. Publishedweakness classified

Affected products

And 1 more affected product. See all after sign-in

Technical detail

CVSS 3.1 vector

Open in the CVSS calculator

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Scored 9.8 by NVD.

How it is reached

  • Attack Vector NetworkExploitable remotely over the network without any special conditions
  • Attack Complexity LowNo special conditions — the attack can be reliably reproduced
  • Privileges Required NoneNo authentication required — anyone can exploit this
  • User Interaction NoneNo user interaction needed — fully automated exploitation

Scope

  • Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

  • Confidentiality HighTotal information disclosure — all data in the component is compromised
  • Integrity HighTotal loss of integrity — attacker can modify any data in the component
  • Availability HighTotal denial of service — the component is completely unavailable

Weaknesses

Sources

References in the record

And 4 more references. See all after sign-in

Watch the software you run.

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We'll flag the next CVE, public exploit or patch for JunOS, not every advisory. This one: actively exploited.