CVE-2026-27212
highpriority · track · 41EPSS 0.005 · 42 %ileexploit · PoCDEEURUUSEPSS · scored 2026-10-27
Swiper is a free and mobile touch slider with hardware accelerated transitions and native behavior. Versions 6.5.1 through 12.1.1 have a Prototype pollution vulnerability. The vulnerability resides in line 94 of shared/utils.mjs, where the indexOf() function is used to check whether user provided input contain forbidden strings. Despite a previous fix that attempted to mitigate prototype pollution by checking whether user input contained a forbidden key, it is still possible to pollute Object.prototype via a crafted input using Array.prototype. The exploit works across Windows and Linux and on Node and Bun runtimes. Any application that processes attacker-controlled input using this package may be affected by the following: Authentication Bypass, Denial of Service and RCE. This issue is fixed in version 12.1.2.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · high–critical · 7.8–9.4
ssvc
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weaknesses
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exploits (1)
Public proof-of-concept and weaponised exploit code.
affected products (6)
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advisories (2)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2026-3046IBM Concert: Mehrere SchwachstellenDeutsch2026-08-26csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in IBM Concert ausnutzen, um beliebigen Programmcode auszuführen, um einen Denial of Service Angriff durchzuführen, um Informationen offenzulegen, um Dateien zu manipulieren, um einen Cross-Site Scripting Angriff durchzuführen, um einen SQL-Injection Angriff durchzuführen und um Sicherheitsvorkehrungen zu umgehen.
- GHSA-hmx5-qpq5-p643Prototype pollution in swiper2026-02-19ghsa · osvUS
### Summary A prototype pollution vulnerability exists in the the npm package swiper (>=6.5.1, < 12.1.2). Despite a previous fix that attempted to mitigate prototype pollution by checking whether user input contained a forbidden key, it is still possible to pollute `Object.prototype` via a crafted input using Array.prototype. The exploit works across Windows and Linux and on Node and Bun runtimes. This issue is fixed in version 12.1.2 ### Details The vulnerability resides in line 94 of shared/utils.mjs where indexOf() function is used to check whether user provided input contain forbidden strings. ### PoC #### Steps to reproduce 1. Install latest version of swiper using npm install 2. Run the following code snippet: ```javascript var swiper = require('swiper'); Array.prototype.indexOf = () => -1; let obj = {}; var malicious_payload = '{"__proto__":{"polluted":"yes"}}'; console.log({}.polluted); swiper.default.extendDefaults(JSON.parse(malicious_payload)); console.log({}.polluted); // prints yes -> indicating that the patch was bypassed and prototype pollution occurred ``` #### Expected behavior Prototype pollution should be prevented and {} should not gain new properties. This should be printed on the console: ``` undefined undefined OR throw an Error ``` #### Actual behavior Object.prototype is polluted This is printed on the console: ``` undefined yes ``` ### Impact This is a prototype pollution vulnerability, which can have severe security implications depending on how swiper is used by downstream applications. Any application that processes attacker-controlled input using this package may be affected. It could potentially lead to the following problems: 1. Authentication bypass 2. Denial of service - Even if an attacker is not able to exploit prototype pollution in swiper, if there is a prototype pollution within the project from other dependencies, modifying global `Array.prototype.indexOf` property can result in crash when swiper.default.extendDefaults is called because swiper makes use of this global property. This can lead to Denial of Service. 3. Remote code execution (if polluted property is passed to sinks like eval or child_process) ### Related CVEs [CVE-2026-25521](https://github.com/advisories/GHSA-rxrv-835q-v5mh) [CVE-2026-25047](https://github.com/advisories/GHSA-2733-6c58-pf27) [CVE-2026-26021](https://github.com/advisories/GHSA-2c4m-g7rx-63q7)
also known as (4)
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sources
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references (10)
External citations — patches, advisories, analysis.
- https://github.com/nolimits4web/swiper/commit/d3e663322a13043ca63aaba235d8cf3900e0c8cfcnnvd
- https://github.com/nolimits4web/swiper/releases/Patchcnnvd
- https://github.com/nolimits4web/swiper/releases/tag/v12.1.2cnnvd
- https://github.com/nolimits4web/swiper/security/advisories/GHSA-hmx5-qpq5-p643cnnvd
- https://github.com/nolimits4web/swiper/commit/d3e663322a13043ca63aaba235d8cf3900e0c8cfenisa_euvd
- https://github.com/nolimits4web/swiper/releases/tag/v12.1.2enisa_euvd
- https://github.com/nolimits4web/swiper/security/advisories/GHSA-hmx5-qpq5-p643enisa_euvd
- https://github.com/nolimits4web/swiper/commit/d3e663322a13043ca63aaba235d8cf3900e0c8cfPatchnvd
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