Kiro IDE CVE-2026-11931

Exploitation requires that the attacker have local authenticated access to the same macOS or Linux system as a victim user who has Kiro IDE installed, has authenticated (creating the token cache file), and is running a version prior to 0.11.133 or has not yet completed a post-upgrade token refresh. The token cache file must be present on the shared filesystem. Exploitation is blocked by: single-user systems where no second local account exists; properly isolated container or VM environments where users cannot cross filesystem boundaries; systems where Kiro IDE has not yet been authenticated post-install (no cache file created); and the Windows platform entirely. The CVSS 4.0 vector PR:L confirms that any standard local user account (no administrator or root required) is sufficient for exploitation.

The CVSS 4.0 score of 6.8 (Medium) accurately captures the threat model: exploitation is local-only (AV:L), requires low privilege (PR:L), and has no complexity barrier (AC:L, AT:N), but is limited to shared multi-user environments. The confidentiality impact is High (VC:H) because authentication tokens typically grant access to backend services and APIs beyond the IDE itself. There is no CISA KEV listing and no public exploit code, which suppresses mass-exploitation risk. EPSS data was not provided; given the local-only vector and absence of public tooling, automated widespread exploitation is unlikely. The realistic risk is elevated on shared Linux development servers, CI/CD build hosts, or multi-tenant macOS environments where multiple user accounts coexist on the same filesystem. Single-user workstations and properly isolated container deployments are not meaningfully affected. The primary threat model is an insider or co-tenant attacker harvesting IDE tokens without needing to exploit any software flaw - simply reading a readable file.

A low-privileged user on a shared Linux development server locates the Kiro IDE token cache file in another user's home directory and reads it directly using standard shell commands, since the 0644 permissions impose no access barrier. The attacker extracts the authentication token from the file and uses it to authenticate to AWS services or other downstream APIs that Kiro IDE is configured to access, impersonating the victim without triggering any authentication event. No exploit code, vulnerability knowledge, or privilege escalation is required - only co-residency on the same filesystem.