CVE-2026-56404

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.
• 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

0.13% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 2.1% of scored records. A rank, not a probability.

NVD base score

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

NVD CVSS vector

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

NVD analysis status

Analyzed. NVD last modified this record on 2026-10-25.

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

2026-06-21 15:45Z4 MO AGO

Last updated

2026-06-22 17:05Z4 MO AGO

Reserved

2026-06-21

Assigning CNA

mitre

Record state

PUBLISHED

Severity

Medium (CVSS 6.9)

CNA CVSS vector

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

Weaknesses

• CWE-190Integer Overflow or WraparoundBase

Data version

5.2

Document digest

2df9abcdd363c8a4314ffcf8a61de71f9f1f1a03497ddb9f76d2202ae060fe34

• github.comhttps://github.com/libexpat/libexpat/pull/1249