CVE-2018-15133
CVE-2018-15133 is a security flaw in Laravel Framework. Attackers can run their own code on Laravel Framework. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 16 Jan 2024.[1]
Laravel Framework is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff. Laravel has published a fix or advice.
Description
CISA calls it a deserialization of untrusted data in Laravel Laravel Framework. In its words: “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).”[1]
The CVE record adds: “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.”[2]
The underlying weakness is deserialization of untrusted data (CWE-502), in MITRE’s list of common software weaknesses.
It scores 8.1 out of 10 on the Common Vulnerability Scoring System, which rates it high, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record doesn’t list version ranges for it; Laravel’s advisory has them[3]. CISA names the product as Laravel Laravel Framework.
Most families won’t have Laravel Framework; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 16 Jan 2024, 1,986 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 6 Feb 2024 to fix it.[1]
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 77%. That’s in the top 1% of the flaws it scores.[4]
CISA assesses it as not automatable: each attack takes some work.
CISA doesn’t say who was attacked, or how.
Fix
Laravel has published a fix or advice.[3] CISA’s required action: “Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.”[1]
- Check whether you use it.Laravel Framework is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
- Send this page to your IT person.Ask them to confirm it’s fixed, or not in use. CISA gave US government agencies until 6 Feb 2024 to fix it.
- If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.
You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 8.1.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at 77%.[4] |
See also
Other Laravel flaws
- CVE-2025-54068, Laravel Livewire: code injection ·
- CVE-2021-3129, Laravel Ignition: file upload ·
Other deserialization of untrusted data flaws
- CVE-2021-23758, Ajax.NET Professional: deserialization of untrusted data ·
- CVE-2026-63077, JetBrains TeamCity: deserialization of untrusted data ·
- CVE-2026-50522, Microsoft SharePoint: deserialization of untrusted data ·
- CVE-2026-58644, Microsoft SharePoint: deserialization of untrusted data ·
- CVE-2026-45659, Microsoft SharePoint Server: deserialization of untrusted data ·
Every Laravel flaw on CISA’s list · Everything added in January 2024
References
- ^ Cybersecurity and Infrastructure Security Agency. “Laravel Deserialization of Untrusted Data Vulnerability”. Known Exploited Vulnerabilities Catalog, added 16 Jan 2024.
- ^ National Institute of Standards and Technology. “CVE-2018-15133 Detail”. National Vulnerability Database, published 9 Aug 2018.
- ^ Laravel. Advisories and fixes: laravel.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.766, percentile 99.5, 31 Oct 2026.
- CVE Program. “CVE-2018-15133”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.