CVE-2021-39906: Improper validation of ipynb files in GitLab CE/EE version 13.5 and above allows an attacker to execute arbitrary JavaScript code on the victim's behalf.

PriorityP350medium6.1CVSS 3.1

AVNACLPRNUIRSCCLILAN

EPSS

60.73%

99.2th percentile

Improper validation of ipynb files in GitLab CE/EE version 13.5 and above allows an attacker to execute arbitrary JavaScript code on the victim's behalf.

Affected

9 ranges

Vendor	Product	Version range	Fixed in
debian	gitlab	< gitlab 15.10.8+ds1-2 (sid)	gitlab 15.10.8+ds1-2 (sid)
gitlab	gitlab	—	—
gitlab	gitlab	—	—
gitlab	gitlab	—	—
gitlab	gitlab	—	—
gitlab	gitlab	>= 13.5.0 < 14.2.6	14.2.6
gitlab	gitlab	>= 14.3.0 < 14.3.4	14.3.4
gitlab	gitlab	>= 14.4.0 < 14.4.1	14.4.1
gitlab	gitlab_ce	—	—

Detection & IOCsextracted from sources · hover to see the quote

→Focus detection on improper validation of .ipynb (Jupyter Notebook) files uploaded or rendered in GitLab CE/EE, which can lead to stored XSS / arbitrary JavaScript execution on behalf of victims. ↗
→Monitor GitLab instances for uploads or rendering of .ipynb files containing embedded JavaScript payloads (e.g., in cell outputs or metadata fields), particularly in repositories accessible to other users. ↗

·Vulnerability affects GitLab CE/EE version 13.5 and above; patched in Debian sid at version 15.10.8+ds1-2. Ensure GitLab instances are upgraded to a fixed release. ↗
·The vulnerability scope is classified as local, meaning exploitation requires the attacker to have some level of access to the GitLab instance (e.g., ability to push or share .ipynb files). ↗

CVSS provenance

nvdv3.16.1MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

nvdv2.04.3MEDIUMAV:N/AC:M/Au:N/C:N/I:P/A:N

osv6.1MEDIUM

vendor_debian8.7HIGH

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