CVE-2026-56306

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 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

0.34% probability of exploitation activity in the next 30 days.

EPSS percentile

Ranks above 27.4% of scored records. A rank, not a probability.

NVD base score

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

NVD CVSS vector

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

Deferred. NVD last modified this record on 2026-06-23.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

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

2026-06-22 21:04Z2 MO AGO

Last updated

2026-06-23 12:11Z2 MO AGO

Reserved

2026-06-20

Assigning CNA

VulnCheck

Record state

PUBLISHED

Severity

Medium (CVSS 5.3)

CNA CVSS vector

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

Weaknesses

• CWE-20Improper Input ValidationClass

Data version

5.2

Document digest

1ae55c2fc634915a1d5971aa6cf73906a930b479d43aaea60895e654b5c67ca6

• github.comGitHub Security Advisory (GHSA-42vv-8j94-24wj)https://github.com/Cap-go/capgo/security/advisories/GHSA-42vv-8j94-24wjvendor-advisory
• www.vulncheck.comVulnCheck Advisory: Capgo - Subkey Enforcement Bypass via x-limited-key-id Header Parsinghttps://www.vulncheck.com/advisories/capgo-subkey-enforcement-bypass-via-x-limited-key-id-header-parsingthird-party-advisory