What is CVE-2026-70427?

CVE-2026-70427 is a medium-severity vulnerability in Jenkins, classified under Improper Link Resolution Before File Access. CVSS score: 4.3/10. Published 2026-08-05.

How severe is CVE-2026-70427?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Vulnerability in Jenkins

CVE-2026-70427

Jenkins 2.575 and earlier, LTS 2.568.1 and earlier does not safely handle symbolic links with effectively empty names during the extraction of `.tar` and `.tar.gz` archives, allowing attackers able to control agent processes to provide crafted archives to the controller to write files to arbitrary locations on the file system, restricted only by file system access permissions of the user running Jenkins.

Published 2026-08-05 · last modified 2026-09-08.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.007 (51.7th percentile), scored 2026-11-03.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 52nd percentile — 51.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.007 · change: +0.002

Affected products

Jenkins
Jenkins Project — versions 2.576, 2.568.2

Weakness classification (CWE)

CWE-59 — Improper Link Resolution Before File Access

References

www.jenkins.io/security/advisory/2026-08-05/ (vendor-advisory, Vendor Advisory)

Frequently asked questions

What is CVE-2026-70427?: CVE-2026-70427 is a medium-severity vulnerability in Jenkins, classified under Improper Link Resolution Before File Access. CVSS score: 4.3/10. Published 2026-08-05.
How severe is CVE-2026-70427?: Medium severity. CVSS v3 base score is 4.3 out of 10.