CVE-2026-56817

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 ImpactpartialSuccessful exploitation gives limited 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

0.69% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 52.4% of scored records. A rank, not a probability.

NVD base score

8.3 (CVSS v4.0), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

NVD analysis status

Analyzed. NVD last modified this record on 2026-07-30.

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

2026-07-21 22:06Z3 MO AGO

Last updated

2026-07-22 15:42Z3 MO AGO

Reserved

2026-06-23

Assigning CNA

GitHub_M

Record state

PUBLISHED

Severity

High (CVSS 8.3)

CNA CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:L/SC:N/SI:N/SA:N

Weaknesses

• CWE-611Improper Restriction of XML External Entity ReferenceBase

Data version

5.2

Document digest

30d9024e6006ea4168e296f05994f3927c81a2af718c2e2a2dfbf0f7d2e397d7

• github.comhttps://github.com/netty/netty/security/advisories/GHSA-4qhr-g3c6-fcfxx_refsource_CONFIRM
• github.comhttps://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003bx_refsource_MISC
• github.comhttps://github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6x_refsource_MISC
• github.comhttps://github.com/netty/netty/releases/tag/netty-4.1.136.Finalx_refsource_MISC
• github.comhttps://github.com/netty/netty/releases/tag/netty-4.2.16.Finalx_refsource_MISC