Dulwich EUVD-2026-106901

Exploitation requires the victim to use dulwich (>=0.22.5, <=1.2.7) to clone or operate on an attacker-crafted repository containing an intermediate directory symlink pointing outside the worktree (e.g. link → ../../.git/hooks) plus a stashed file under that symlinked path. The victim must then perform the specific stash workflow - checkout a branch, stash.push(), checkout back to the branch holding the symlink, and stash.pop() - because validate_path() only blocks INVALID_DOTNAMES and performs no filesystem symlink detection, and build_file_from_blob() has no O_NOFOLLOW protection. LIMITING FACTORS: local access/operation only (AV:L), mandatory multi-step user interaction (UI:P), the attacker cannot act without the victim processing an untrusted repository, and RCE is only realized when a subsequent git checkout triggers the planted post-checkout hook. Highest exposure is developer workstations and CI/automation that ingest untrusted repositories.

This is a genuine but conditional code-execution risk, not a drive-by remote compromise. The input provides only a CVSS 4.0 vector (CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P, score 7.3) and no CVSS 3.1 vector. Key signals: attack vector is LOCAL (AV:L), there is an attack requirement (AT:P) and required user interaction (UI:P), while vulnerable-system impact is HIGH across confidentiality, integrity and availability (VC:H/VI:H/VA:H) - consistent with arbitrary file write leading to RCE via a planted .git/hooks/post-checkout. PR:N technically means no pre-existing privileges on the victim's machine, but exploitation is gated by the victim voluntarily cloning an attacker-controlled repository and performing a specific stash push/checkout/pop sequence, so 'unauthenticated' here does not mean 'unattended remote.' No EPSS score, no CISA KEV entry, and no explicit POC/exploit-code flag were supplied, so there is no public exploitation-probability signal; the GHSA/VulnCheck advisories describe a detailed, reproducible attack recipe but no weaponized exploit artifact is referenced. Net: real priority for developer/CI environments that process untrusted repositories with dulwich, but the local vector plus multi-step user interaction keeps real-world mass-exploitation risk well below what the 7.3 and 'RCE' tag might suggest in isolation.

An attacker publishes a malicious Git repository whose branches contain an intermediate directory symlink (e.g. link → ../../.git/hooks) and a stashed payload file at link/post-checkout. When a victim using dulwich clones the repo and runs the specific stash push/checkout/pop sequence, stash.pop() follows the symlink and writes the payload to .git/hooks/post-checkout, which executes on the next checkout. No weaponized public exploit is referenced in the input, but the advisory provides a full step-by-step reproduction; attack complexity is raised by the required local AV:L and victim-driven stash operations (AT:P/UI:P).