CVE-2026-84383

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.
• 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

0.71% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 53.5% 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

Deferred. NVD last modified this record on 2026-09-18.

Red Hat severity

Critical. 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

2026-09-18 15:55Z1 MO AGO

Last updated

2026-09-18 16:11Z1 MO AGO

Reserved

2026-09-01

Assigning CNA

GitHub_M

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-787Out-of-bounds WriteBase

Data version

5.2

Document digest

42d89c92927513bd3f31a21d072a7c4218da40bfb885bb4707365b07c3c037f3

• github.comhttps://github.com/strukturag/libheif/security/advisories/GHSA-g89c-p67h-r497x_refsource_CONFIRM
• github.comhttps://github.com/strukturag/libheif/commit/f4fb8bde4704ebb46e46ff9fb94407c9774153b2x_refsource_MISC
• github.comhttps://github.com/strukturag/libheif/releases/tag/v1.23.2x_refsource_MISC