CVE-2026-16389

Exploitation

Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.

SSVC decision

• ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
• AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
• 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

0.64% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 50.3% of scored records. A rank, not a probability.

NVD base score

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

NVD CVSS vector

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

NVD analysis status

Modified. NVD last modified this record on 2026-10-24.

Red Hat severity

Moderate. 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

2026-07-21 12:38Z3 MO AGO

Last updated

2026-08-10 17:18Z2 MO AGO

Reserved

2026-07-20

Assigning CNA

mozilla

Record state

PUBLISHED

Severity

Critical (CVSS 9.8)

CNA CVSS vector

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

Weaknesses

• CWE-190Integer Overflow or WraparoundBase
• CWE-787Out-of-bounds WriteBase

Data version

5.2

Document digest

46548337301564701819fb0008a62ce3f7b3ff0e34be75981a79ce2c599006d2

• bugzilla.mozilla.orghttps://bugzilla.mozilla.org/show_bug.cgi?id=2043887
• www.mozilla.orghttps://www.mozilla.org/security/advisories/mfsa2026-68/
• www.mozilla.orghttps://www.mozilla.org/security/advisories/mfsa2026-71/
• lists.debian.orghttps://lists.debian.org/debian-lts-announce/2026/08/msg00019.html