GitLab CE/EE unauthenticated path traversal in repository commits API, arbitrary file read, CVSS 10.0

NCSC Switzerland's own advisory, published 2026-09-11, independently confirms CVE-2026-87719 (CVSS 9.9, GitLab EE only) alongside CVE-2026-85706 in the same posting. GitLab's own release notes describe the flaw: "GitLab has remediated an issue that, under certain conditions, could allow an authenticated user with Duo Chat access to obtain Advanced Search instance configurations and sensitive credentials using a specially crafted GraphQL subscription argument to bypass serialization and perform server object lookup" (GitLab, 2026-09-10). Affected versions are EE only, 18.3 up to the same 19.1.8/19.2.6/19.3.2 fixed releases named above; no exploitation is confirmed for this CVE. The same release also fixed CVE-2026-88765 (CVSS 8.5, GitLab EE only, sourced from GitLab's own release notes alone with no independent confirmation found): "GitLab has remediated an issue that, under certain conditions, could allow an authenticated user to achieve remote code execution by importing a specially crafted Git project export to overflow the Unicode conversion buffer used in Advanced Search indexing" (GitLab, 2026-09-10). This flaw's affected-version floor, EE 12.3, is substantially older than the other two flaws in this release, so any EE instance that has deferred upgrades for a long period carries the largest exposure window for this specific remote-code-execution path.

By inference from the mechanism, audit logs for GraphQL subscription requests with abnormal argument shapes targeting Advanced Search, and for an Advanced Search reindex operation immediately following a Git project import from an external or untrusted source, are the discriminators for these two additional flaws.

NCSC Switzerland's Cyber Security Hub posting for this advisory was edited twice more inside this window. On 2026-09-14 the posting's own edit-history record states "CVE-2026-87719 is known as actively exploited" (NCSC Switzerland, 2026-09-14), moving the GitLab EE deserialization flaw from patch-available-only to exploited; that same-day posting carries no further detail on this CVE specifically (no campaign, no named cluster, no second source, and CISA's KEV catalog does not list it) so this status rests on NCSC Switzerland's own brief statement alone rather than the broader corroboration CVE-2026-85706 already carries. On 2026-09-15 the same posting was updated again, its status field now reading "Actively exploited, Proof of Concept available" for CVE-2026-85706 (NCSC Switzerland, 2026-09-15), and linking a public working proof of concept whose repository dates from 2026-09-11 (guneykabel, 2026-09-11). No new affected-version information accompanies either update; GitLab 19.3.2/19.2.6/19.1.8 remain the fixed releases for both CVEs.

Any self-managed instance still unpatched should now be treated as likely already probed on both fronts: the file-read path with a public exploit script circulating, and, for any instance with Duo Chat-enabled accounts, the Advanced Search credential-exposure path CVE-2026-87719 opens.

On 2026-09-23 GitLab released 19.0.9 and 18.11.12, backporting the fixes for CVE-2026-85706 and CVE-2026-87719 to self-managed installations that cannot immediately move to 19.1 or later (GitLab, 2026-09-23). Instances on 18.7 to 18.11 or on 19.0 are therefore fixed by 18.11.12 or 19.0.9 rather than only by an upgrade to a newer minor release. GitLab says these versions contain only those security fixes (GitLab, 2026-09-23), so GitLab EE on the backport trains stays exposed to CVE-2026-88765, which is fixed from 19.1.8 (GitLab, 2026-09-10). GitLab has published three detections for CVE-2026-85706 exploitation attempts: reads of gitlab.yml, inclusion through the metadata.path parameter, and file-path enumeration (GitLab, 2026-09-10). NCSC Switzerland's exploited status for CVE-2026-87719 rests on its post's edit history; the update text of the same day concerns CVE-2026-85706's KEV listing (NCSC Switzerland, 2026-09-15).