CVE-2026-8391

MEDIUM
Published May 12, 2026 Modified May 13, 2026 CWE-20 CWE-79 CWE-119

Description

Other issue in the JavaScript Engine component. This vulnerability was fixed in Firefox 150.0.3.

CVSS v3.1 Score

5.3
MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS — Exploit Prediction

0.0011
Probability of exploitation
0.29%
Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-20 Improper Input Validation
CWE-79 Cross-site Scripting (XSS)
CWE-119 Buffer Overflow

Affected Products

Vendor Product
mozilla firefox

References

Frequently Asked Questions

What is CVE-2026-8391? +
Other issue in the JavaScript Engine component. This vulnerability was fixed in Firefox 150.0.3. It has a CVSS v3.1 base score of 5.3 (MEDIUM).
How severe is CVE-2026-8391? +
CVE-2026-8391 has a CVSS v3.1 score of 5.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0011, placing it in the 0th percentile for exploitation probability.
What products are affected by CVE-2026-8391? +
CVE-2026-8391 affects products from mozilla, specifically: firefox. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2026-8391? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2025-13826

Zervit's portable HTTP/web server is vulnerable to remote DoS attacks when a configuration reset request is made. The vulnerability is …
CVE-2026-44522

Note Mark is an open-source note-taking application. From 0.13.0 to before 0.19.4, the Note Mark application allows authenticated users to …
CVE-2024-54011

Penetration Testing engineers at Amazon have discovered a flaw where the camera system fails to properly handle data supplied in …
CVE-2026-6409

A Denial of Service (DoS) vulnerability exists in the Protobuf PHP library during the parsing of untrusted input. Maliciously structured …
CVE-2025-23202

Bible Module is a tool designed for ROBLOX developers to integrate Bible functionality into their games. The `FetchVerse` and `FetchPassage` …
CVE-2025-24501

An improper input validation allows an unauthenticated attacker to alter PAM logs by sending a specially crafted HTTP request.

Don't wait for an exploit

Scan your website for vulnerabilities like CVE-2026-8391 — free, no signup required.

Start Free Scan