CVE-2018-15133: Laravel Deserialization of Untrusted Data Vulnerability

Should you act?

Exploited: patch now if you run it

CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Yes, if you run Laravel Laravel Framework. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2024-01-16, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2024-02-06; treat that as the outer limit, not the target.
• EPSS 76.6%, percentile 99.5: FIRST’s model estimates a 76.6% chance of exploitation activity in the next 30 days, higher than 99.5% of all scored CVEs (very high). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.

What it is

In Laravel Framework through 5.5.40 and 5.6.x through 5.6.29, remote code execution might occur as a result of an unserialize call on a potentially untrusted X-XSRF-TOKEN value. This involves the decrypt method in Illuminate/Encryption/Encrypter.php and PendingBroadcast in gadgetchains/Laravel/RCE/3/chain.php in phpggc. The attacker must know the application key, which normally would never occur, but could happen if the attacker previously had privileged access or successfully accomplished a previous attack.

CISA’s summary

Laravel Framework contains a deserialization of untrusted data vulnerability, allowing for remote command execution. This vulnerability may only be exploited if a malicious user has accessed the application encryption key (APP_KEY environment variable).

Weakness type: CWE-502.

Product: Laravel Laravel Framework · Assigned by: mitre · Published: 2018-08-09

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: high (needs special conditions)
• Privileges required: none (no login)
• User interaction: none
• Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: added 2024-01-16; federal due date 2024-02-06. Known ransomware use: Unknown.
• CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
• CISA SSVC assessment: exploitation active, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 76.57% probability of exploitation activity in the next 30 days; percentile 99.5.

Timeline

• 2018-08-09 — CVE record published by mitre
• 2024-01-16 — Added to CISA’s Known Exploited Vulnerabilities catalog
• 2024-02-06 — CISA remediation deadline for US federal agencies
• 2025-10-21 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vendor and project advisories, patches

1. Listed in CISA KEV notes (laravel.com) laravel.com

Vulnerability records

1. CVE.org record CVE-2018-15133 cve.org
2. NVD entry CVE-2018-15133 nvd.nist.gov

Government

1. CISA Known Exploited Vulnerabilities catalog entry cisa.gov

Other references from the CVE record and advisory

1. packetstormsecurity.com packetstormsecurity.com

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