How severe is CVE-2023-36844?

CVE-2023-36844 has a CVSS score of 5.3/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2023-36844?

Affected package information for CVE-2023-36844 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2023-36844?

No fixed release is recorded for CVE-2023-36844 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.

How do I detect CVE-2023-36844 in my code and dependencies?

Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).

How do I mitigate CVE-2023-36844 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2023-36844 actively exploited in the wild?

Yes. There are 7 known exploit references for CVE-2023-36844, including 5 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2023-36844?

CVE-2023-36844 has an EPSS (Exploit Prediction Scoring System) score of 90.0%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

Is CVE-2023-36844 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2023-36844 (Juniper Junos OS EX Series PHP External Variable Modification Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2023-11-13. CISA required all US federal civilian agencies to remediate this vulnerability by 2023-11-17. The required action was: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2023-36844?

CVE-2023-36844 is classified as CWE-473 (CWE-473). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Is there exploit tooling available for CVE-2023-36844?

A Nuclei detection template exists for CVE-2023-36844, meaning automated scanners can fingerprint it. A Metasploit module references CVE-2023-36844, which lowers the barrier to weaponization. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2023-36844 published, and has it been updated?

CVE-2023-36844 was published on August 17, 2023 and was last updated on October 21, 2025. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🛡️

CISA KEV · ACTIVELY EXPLOITED

MEDIUM severity

CVE-2023-36844

MEDIUM

CVE-2023-36844 is a medium-severity (CVSS 5.3) CWE-473 vulnerability. It is in CISA's Known Exploited Vulnerabilities catalog (added 2023-11-13) — treat it as actively exploited and patch now. No vendor fix is recorded yet; mitigation options are listed below.

A PHP External Variable Modification vulnerability in J-Web of Juniper Networks Junos OS on EX Series allows an unauthenticated, network-based attacker to control certain, important…

Published

Aug 17, 2023

Updated

Oct 21, 2025

Affected

1 product

Patched

See advisory

Exploits

7 known

Exploitation data as of Oct 21, 2026 · OSV.dev, NVD, CISA KEV, FIRST.org (EPSS)

Exploitation Status

Actively exploited in the wild

Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2023-11-13. Federal agencies were required to remediate by 2023-11-17.
CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2023-36844.

EPSS Exploitation Probability

via FIRST.org ↗

90.0%probability of exploitation in next 30 days

Very High Risk0.00%

Lower risk than most CVEs100th percentile — riskier than 100% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2023-36844 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 395,249 CVEs with a current EPSS score, this one falls in the 50–90% band (highlighted). Counts from FIRST.org, log-scaled.

Description

Using a crafted request an attacker is able to modify

certain PHP environment variables leading to partial loss of integrity, which may allow chaining to other vulnerabilities. This issue affects Juniper Networks Junos OS on EX 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 22.3R3-S1;

22.4 versions

prior to

22.4R2-S2, 22.4R3;

23.2 versions prior to

23.2R1-S1, 23.2R2.

Affected Products

1 product · 94 configurations

junosjuniper

< 20.4

10 versions

20.421.121.221.321.422.122.222.322.423.2

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.