CVE-2026-77939

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

0.61% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 48.5% of scored records. A rank, not a probability.

NVD base score

7.1 (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:H/VI:N/VA:N/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

Deferred. NVD last modified this record on 2026-09-08.

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

2026-08-28 17:06Z2 MO AGO

Last updated

2026-08-29 11:47Z2 MO AGO

Reserved

2026-08-21

Assigning CNA

VulnCheck

Record state

PUBLISHED

Severity

High (CVSS 7.1)

CNA CVSS vector

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

Weaknesses

• CWE-94Improper Control of Generation of Code ('Code Injection')Base
• CWE-1336Improper Neutralization of Special Elements Used in a Template EngineBase

Data version

5.2

Document digest

74dfa158afa2d6f82e8b96e0f7572c271f95d5651f20bd2e5bce72ce772c6bbd

• github.comResearcher Disclosurehttps://github.com/flextype/flextype/issues/595technical-descriptionexploit
• www.vulncheck.comhttps://www.vulncheck.com/advisories/flextype-cms-dev-rce-via-post-api-v1-query-endpointthird-party-advisory