CVE-2026-56821

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

0.21% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 12.2% of scored records. A rank, not a probability.

NVD base score

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

NVD CVSS vector

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

NVD analysis status

Analyzed. NVD last modified this record on 2026-08-07.

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

2026-07-28 23:07Z3 MO AGO

Last updated

2026-07-31 16:12Z3 MO AGO

Reserved

2026-06-23

Assigning CNA

GitHub_M

Record state

PUBLISHED

Severity

High (CVSS 7.4)

CNA CVSS vector

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

Weaknesses

• CWE-299Improper Check for Certificate RevocationBase
• CWE-93Improper Neutralization of CRLF Sequences ('CRLF Injection')Base

Data version

5.2

Document digest

3d4ea12b086a0a5f20de006074afba2fe1d282ff980996dcd3b90006e82e916a

• github.comhttps://github.com/netty/netty/security/advisories/GHSA-g7hg-vrcf-mvmrx_refsource_CONFIRM