openssl-encrypt EUVD-2026-67053

Exploitation requires two simultaneous conditions: (1) the victim must use the legacy Tk GUI interface - specifically the SettingsTab, which invokes the vulnerable CONFIG_FILE resolution in crypt_settings.py at line 84 - rather than the CLI or programmatic API; and (2) the attacker must have pre-positioned a malicious crypt_settings.json in the specific directory from which the victim launches the application (the process CWD at launch time). The flaw does not trigger in non-GUI usage. Limiting factors include: the attacker requires local filesystem write access to a directory the victim uses as CWD, the victim must actively use the Tk GUI for an encryption operation during that session, and no special configuration beyond launching the GUI from the compromised directory is needed to trigger the downgrade.

The supplied CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:N, score 8.7) is materially inconsistent with the described attack mechanism, which requires the attacker to pre-position a file on the local filesystem in the victim's CWD - an operation that is local, not network-reachable. A more accurate vector would use AV:L and UI:A (victim must actively launch the GUI from the compromised directory); the supplied vector should not be used as the basis for prioritization. No EPSS data is available to quantify exploitation probability. The CVE is not listed in CISA KEV and no public exploit code has been identified. Real-world impact is limited to users of the legacy Tk GUI who both operate from a directory an attacker can write to and perform encryption during that session; CLI or programmatic use of the library is entirely unaffected. When exploitation conditions are met, however, the confidentiality impact is severe: weakened ciphertext is vulnerable to near-instant offline attack.

An attacker with write access to a directory the victim commonly uses as CWD - such as a shared Downloads folder or a directory created by extracting an archive - plants a crypt_settings.json specifying sha256:1 with memory-hard KDFs disabled. When the victim launches the Tk GUI from that directory, the application silently loads attacker-controlled KDF settings, bypasses the weak-KDF preflight, and produces ciphertext derived from a single SHA-256 round. The attacker then obtains the ciphertext and recovers plaintext via near-instant offline brute-force.