SiYuan CVE-2026-82653

Exploitation requires the attacker to control a package name in SiYuan's bazaar marketplace (or a notebook name), matching PR:L - a submission/publishing capability rather than anonymous access. The payload only executes when the victim performs a specific triggering action: uninstalling the malicious bazaar package, or unlocking an encrypted notebook whose name carries the payload (UI:P/passive interaction). Limiting factors: the victim must actually install then uninstall the package (or open the crafted notebook), the target must be running SiYuan before v3.8.1, and the attacker needs a route to place content into the bazaar name or notebook name field. There is no default-configuration, zero-interaction remote path.

The input assigns CVSS 4.0 base 9.3 (AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L). The network vector and low complexity are consistent with delivering a payload through a public bazaar package, but two factors temper real-world severity: PR:L means the attacker must be able to publish/submit a package (some privilege or account), and UI:P means the payload only fires on a specific victim action (uninstalling the package or unlocking an encrypted notebook) - it is not click-free drive-by. No EPSS score, KEV listing, or POC was provided, so there is no signal of automated or in-the-wild exploitation; the high score is driven by potential impact rather than demonstrated ease. The SC:H/SI:H subsequent-system ratings in the supplied vector appear generous for browser-context XSS in a note app and should be treated as the vendor/reporter's view rather than independently confirmed. Net: a genuine high-severity XSS worth prompt patching for SiYuan users, but not an emergency mass-exploitation scenario on current evidence.

An attacker publishes a bazaar package whose name field contains an XSS payload (e.g., an img/script construct). A SiYuan user installs it and later chooses to uninstall it; confirmDialog() renders the crafted name via innerHTML, executing the attacker's script in the user's SiYuan session to exfiltrate notes, tokens, or manipulate the workspace. No public POC was provided, and the attack depends on the victim performing the uninstall (or unlocking a maliciously named encrypted notebook).