CVE-2026-8389

Exploitation

Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.

SSVC decision

• ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
• AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
• Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.42% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 36.3% of scored records. A rank, not a probability.

NVD base score

8.8 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

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

NVD analysis status

Modified. NVD last modified this record on 2026-10-26.

Red Hat severity

Important. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2026-05-12 12:36Z5 MO AGO

Last updated

2026-07-15 02:48Z3 MO AGO

Reserved

2026-05-12

Assigning CNA

mozilla

Record state

PUBLISHED

Severity

High (CVSS 8.8)

CNA CVSS vector

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

Weaknesses

• CWE-119Improper Restriction of Operations within the Bounds of a Memory BufferClass
• CWE-686Function Call With Incorrect Argument TypeVariant
• CWE-843Access of Resource Using Incompatible Type ('Type Confusion')Base
• CWE-733Compiler Optimization Removal or Modification of Security-critical CodeBase

Data version

5.2

Document digest

23953be1556d792f1da86e4db2ecb81fe902a08782072c71ab2a62c9da8c6f5e

• bugzilla.mozilla.orghttps://bugzilla.mozilla.org/show_bug.cgi?id=2036983
• www.mozilla.orghttps://www.mozilla.org/security/advisories/mfsa2026-45/
• github.comhttps://github.com/crixpwn/CVE-2026-8389exploit
• access.redhat.comhttps://access.redhat.com/security/cve/CVE-2026-8389vdb-entryx_refsource_REDHAT
• bugzilla.redhat.comRHBZ#2476466https://bugzilla.redhat.com/show_bug.cgi?id=2476466issue-trackingx_refsource_REDHAT
• security.access.redhat.comhttps://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-8389.jsonx_sadp-csaf-vex