CVE-2026-54159: prestashop/ps_facetedsearch: PHP Object Injection in faceted search cache allows unauthenticated RCE

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.8%, percentile 54: FIRST’s model estimates a 0.8% chance of exploitation activity in the next 30 days, higher than 54% of all scored CVEs (moderate). 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.
• Only applies if your dependency tree includes prestashop/ps_facetedsearch (Composer (PHP)) >= 3.0.0, < 4.0.4, fixed in 4.0.4. Check your lockfile, including transitive dependencies.

What it is

PrestaShop psfacetedsearch is a module that adds layered navigation filters. From 3.0.0 until 4.0.4, the psfacetedsearch module rebuilds selected search filters from the request URL, and the value of a slider filter, price or weight, is taken from the URL without sufficient validation and stored in an internal filter-block cache where it is serialized and later read back with a raw native unserialize() in src/Filters/Block.php. By crafting that value, an unauthenticated attacker can smuggle a malicious serialized PHP object into the cache, and when it is deserialized, a gadget chain writes an arbitrary PHP file inside the modules/psfacetedsearch/ directory, which is then used as a webshell to run commands on the server. This issue is fixed in version 4.0.4.

From the GitHub advisory

Impact

A PHP Object Injection vulnerability affects the PrestaShop module psfacetedsearch.

The module rebuilds the selected search filters from the request URL. The value of a slider filter (price or weight) is taken from the URL without sufficient validation, then stored in an internal filter-block cache where it is serialized and later read back with a raw native unserialize(). By crafting that value, an attacker can smuggle a malicious serialized PHP object into the cache. When it is deserialized, a gadget chain writes an arbitrary PHP file inside the module directory, which is then used as a webshell to run commands on the server.

Who is impacted

Any shop using a vulnerable version of psfacetedsearch that displays a filter template containing a slider filter (price or weight). Exploitation is remote and unauthenticated, a single crafted front-office request is enough, and leads to remote code execution and full compromise of the shop and its server.

Weakness type: CWE-74.

Product: prestashop/ps_facetedsearch (Composer (PHP)) · Assigned by: GitHub_M · Published: 2026-07-17

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: none
• Scope: changed (can affect other components)

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: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable yes, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.75% probability of exploitation activity in the next 30 days; percentile 54.

Timeline

• 2026-07-10 — GitHub-reviewed advisory GHSA-m5f5-28qr-9g9r published (critical)
• 2026-07-17 — CVE record published by GitHub_M
• 2026-07-20 — CVE record last updated

Sources and references

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

Vulnerability records

1. GitHub Advisory GHSA-m5f5-28qr-9g9r github.com
2. CVE.org record CVE-2026-54159 cve.org
3. NVD entry CVE-2026-54159 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. github.com github.com

Critical Composer (PHP) advisories · Today’s Security Digest