jQuery before 3.4.0, as used in Drupal, Backdrop CMS, and other products, mishandles jQuery.extend(true, {}, ...)…
SummaryAI-written · claude-haiku-5-5AI-written · claude-haiku-5-5Written by a language model from the source data on this page. Not reviewed by a person. Generated 29 Oct 2026.
The flaw is in jQuery versions before 3.4.0, as bundled in products such as Drupal and Backdrop CMS, where the jQuery.extend(true, {}, ...) deep-merge function mishandles Object.prototype pollution. An attacker who can supply an unsanitized source object containing an enumerable __proto__ property can extend the native Object.prototype, with the exact conditions of exposure depending on whether the application passes untrusted input into that function.
Official description · CVE.orgSource dataSource dataCopied from an authoritative feed: NVD, CVE.org, CISA KEV, FIRST EPSS or MITRE CTID mappings, or labelled by the annotators of a published dataset. Copied from CVE.org.
jQuery before 3.4.0, as used in Drupal, Backdrop CMS, and other products, mishandles jQuery.extend(true, {}, ...) because of Object.prototype pollution. If an unsanitized source object contained an enumerable __proto__ property, it could extend the native Object.prototype.
Priority scorePatchfirst’s 0 to 100 ranking. It adds points for CISA KEV listing, ransomware use, EPSS, threat reports, public exploit code and CVSS. Every CVE page shows the breakdown.Breakdown
61.7 / 100
Exploited
Yes, in VulnCheck KEV
Reports
0
Tactics
0/15
Exploitation timelineDated milestones for a CVE: when it was disclosed, when exploit code became public, when exploitation was confirmed, and when threat reports named it.
First seen exploited 21 months after disclosure. Public exploit code (PoC-in-GitHub) was available 20 days before disclosure.
Patch historyEarlier and later CVEs in the same code, in date order. It shows when a fix was bypassed or incomplete and which version finally fixed it.
3 related vulnerabilities in the same code over 2 years.
Same bug familyLinked by evidence that a fix failed or the same code was patched again. Oldest first.
CVE-2012-6708jQuery before 1.9.0 is vulnerable to Cross-site Scripting (XSS)…18 Jan 2018
relatedMedium
Why these are linked: Link confidenceHow strong the evidence is that two CVEs are related. High: stated in the CVE text or linked in an advisory, or the same code was patched one release apart. Medium: the same code, or a version step plus a similar description. Low: similar description only.
This CVECVE-2019-11358jQuery before 3.4.0, as used in Drupal, Backdrop CMS, and other…19 Apr 2019
relatedMedium
Why these are linked: Link confidenceHow strong the evidence is that two CVEs are related. High: stated in the CVE text or linked in an advisory, or the same code was patched one release apart. Medium: the same code, or a version step plus a similar description. Low: similar description only.
CVE-2020-7656jquery prior to 1.9.0 allows Cross-site Scripting attacks via…19 May 2020
MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. techniques
No techniques linked
No ATT&CK techniques are linked to this CVE yet. MITRE CTID has not mapped it, and no report passage in the corpus ties it to a technique.
Am I affected? What do I upgrade to?
From GitHub Security Advisories and OSVSourceSource dataCopied from an authoritative feed: NVD, CVE.org, CISA KEV, FIRST EPSS or MITRE CTID mappings, or labelled by the annotators of a published dataset. GitHub Security Advisories and OSV.
7 packages in 6 ecosystems. Main package: jquery (npm, NuGet).