CVE-2026-27212: 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 pol...

Description

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.

Metrics

CVSS 3.1

7.8/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS 4.0

9.4/10

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

0.40%

31.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-1321

Affected Software

Vendor	Product	Versions
Swiperjs	Swiper	>= 6.5.1, < 12.1.2

References

Timeline

Published: Feb 21, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-27212?

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.

How severe is CVE-2026-27212?

CVE-2026-27212 has a CVSS score of 9.4/10 (CRITICAL severity). The EPSS model estimates a 0.40% probability of exploitation in the next 30 days.

How do I fix CVE-2026-27212?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.