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CVE-2023-36851: Juniper Junos OS SRX Series Missing Authentication for Critical Function Vulnerability

criticalknown exploitedCVE-2023-36851
Actively exploited. At least one CVE in this advisory is listed in the CISA Known Exploited Vulnerabilities catalog — exploitation has been observed in the wild. Treat remediation as urgent.
Juniper Junos OS on SRX Series contains a missing authentication for critical function vulnerability that allows an unauthenticated, network-based attacker to cause limited impact to the file system integrity. With a specific request to webauth_operation.php that doesn't require authentication, an attacker is able to upload arbitrary files via J-Web, leading to a loss of integrity for a certain part of the file system, which may allow chaining to other vulnerabilities.

CSIRTS triage

vendor: Juniperproduct: Junos OSAuthentication bypassOtheraffected: SRX Series
What
The vulnerability allows an unauthenticated attacker to upload arbitrary files via J-Web, impacting file system integrity.
Who is affected
Deployments of Juniper Junos OS on SRX Series.
Urgency
Remediation is urgent due to active exploitation and critical severity.
Action
Apply the latest security patch provided by Juniper.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source
CISA Known Exploited Vulnerabilities (US · database · site)
Severity
critical
Published
2023-11-13
Exploitation
Observed in the wild (CISA KEV)

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2023-36851

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Referenced CVEs

CVECSIRTS overviewExternal
CVE-2023-36851coverage & exploitation statusNVD · CVE.org

Recent advisories for Juniper Junos OS

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

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