CVE-2026-66881

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

0.42% probability of exploitation activity in the next 30 days.

EPSS percentile

Ranks above 34.6% of scored records. A rank, not a probability.

NVD base score

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

NVD CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/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 2026-08-10.

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

2026-08-05 19:43Z1 MO AGO

Last updated

2026-08-06 13:03Z29 DAYS AGO

Reserved

2026-07-28

Assigning CNA

EEF

Record state

PUBLISHED

Severity

High (CVSS 7.0)

CNA CVSS vector

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

Weaknesses

• CWE-23Relative Path TraversalBase

Data version

5.2

Document digest

37e8731c8e8fe555f0423b37183e46c5b64902ab16d5a9773f2b60532785eeb0

• github.comhttps://github.com/livebook-dev/livebook/security/advisories/GHSA-r4h8-2xpq-v48gvendor-advisoryrelated
• cna.erlef.orghttps://cna.erlef.org/cves/CVE-2026-66881.htmlrelated
• osv.devhttps://osv.dev/vulnerability/EEF-CVE-2026-66881related
• github.comhttps://github.com/livebook-dev/livebook/commit/1443dd23df6e7b9203b6797f0695a807aeb81ddepatch
• github.comhttps://github.com/livebook-dev/livebook/commit/acf4cb8c0c79b89c795b180f061be7de2d8b5aa9patch
• github.comhttps://github.com/livebook-dev/livebook/commit/50f86982ebf36c22abeb379b55ec0f2859c83bb9patch