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CVE-2026-54133 jmespath CVE debrief

A critical vulnerability, CVE-2026-54133, was discovered in jmespath.php, a PHP library for declaratively specifying how to extract elements from a JSON document. The vulnerability has a CVSS score of 9.8 and can allow attackers to execute arbitrary PHP code. The issue arises when using `JmesPathCompilerRuntime` with an attacker-controlled JMESPath expression, which can generate and execute malicious PHP code. The vulnerability is patched in version 2.9.1 and later.

Vendor
jmespath
Product
jmespath.php
CVSS
CRITICAL 9.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-12
Original CVE updated
2026-06-15
Advisory published
2026-06-12
Advisory updated
2026-06-15

Who should care

Developers and administrators using jmespath.php in their applications should be aware of this vulnerability and take steps to mitigate it.

Technical summary

The vulnerability occurs when `JmesPathCompilerRuntime` is used with an attacker-controlled JMESPath expression. The compiler emits parsed JMESPath function names into generated PHP source without sufficient escaping, allowing attackers to inject malicious PHP code. The issue can be mitigated by disabling `JP_PHP_COMPILE` and using the default `AstRuntime` for untrusted expressions.

Defensive priority

High

Recommended defensive actions

  • Upgrade to version 2.9.1 or later of jmespath.php
  • Disable `JP_PHP_COMPILE` and use the default `AstRuntime` for untrusted expressions
  • Avoid using `JmesPathCompilerRuntime` with attacker-controlled expressions

Evidence notes

The vulnerability is patched in version 2.9.1 and later. As a workaround, disable `JP_PHP_COMPILE` and do not use `JmesPathCompilerRuntime` with attacker-controlled expressions.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-54133 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-54133

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-54133 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-54133

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.