EUVD-2026-114080
GHSA-cqj4-h3hg-hjvc
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessAuthenticate as Pro subscriber
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ExploitObtain victim's chat ID
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ExecutionCall chatsMessages.update with victim chatId
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ImpactInject crafted messages into victim AI chat history
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Object-level authorization, IDOR prevention
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| Exploitation Conditions | Exploitation requires an authenticated account with Pro-subscriber privileges (CVSS PR:L) using the Tamery cloud sync feature, and the attacker must know or enumerate the target's chat ID - the chatsMessages.update handler accepts a client-supplied chatId without verifying the caller owns it. No user interaction by the victim is needed (UI:N) and no non-default configuration is required beyond using cloud sync. Limiting factors that reduce real-world risk: it is a write-only (integrity) primitive into the victim's chat history with no read of victim data, it is bounded to accounts holding a Pro subscription, it depends on obtaining a valid victim chatId, and affected versions are 0.26.1 up to the fixed 0.99.0. |
| Impact | The vendor CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N, 5.3 medium) describes a network-reachable, low-complexity, low-privilege flaw with no user interaction whose only impact is low integrity (VI:L) - specifically an unauthorized cross-user write, with no confidentiality (VC:N) or availability (VA:N) impact. This is consistent with CWE-639 (authorization bypass via user-controlled key / IDOR): an authenticated Pro subscriber can write into another user's data but cannot read it. The vuln.today decision label is 'this_month', not act_now/emergency, which aligns with the medium score. It is NOT in CISA KEV (no confirmed active exploitation), and no EPSS score is provided in the input, so widespread-exploitation probability cannot be quantified - STATE EXPLICITLY: EPSS is missing and KEV status is negative. A public technical writeup of the mechanism exists (hackmd 'broken ownership cross-user write') alongside the patched source and commit, so the flaw is well-understood, but this is analysis rather than confirmed weaponized exploit code. Net: a genuine but bounded, integrity-only authorization defect requiring an authenticated Pro account plus knowledge of a victim's chat ID - a real issue to patch on a normal cycle, not a drop-everything emergency, and not a high-CVSS-but-no-real-risk case either. |
| Exploit ScenarioDerived | An authenticated Pro subscriber obtains or guesses another user's chat ID and calls the cloud-sync chatsMessages.update handler supplying that victim chatId, which the API fails to verify against the caller's ownership. The attacker thereby writes messages with arbitrary parts and metadata into the victim's AI chat history. A public technical writeup describes this broken-ownership mechanism, but no verified working exploit tool is cited. |
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Alert meAnalysisAIv1 – Oct 30, 2026
An authorization bypass in Tamery (formerly Conar) cloud sync lets an authenticated Pro subscriber write messages into another user's AI chat history by supplying a victim's chatId to the chatsMessages.update handler, which never verifies that the caller owns the chat. Versions 0.26.1 through 0.98.x are affected, and the flaw is an integrity-only primitive (CVSS 4.0: 5.3 medium; independently assessed CVSS 3.1: 5.3, VC:N/VI:L/VA:N) that grants no read access to victim data. A public technical writeup describing the cross-user write exists; it is not verified as working exploit code, and no CISA KEV entry or confirmed active exploitation was provided. Fix is available in 0.99.0.
RemediationAI
Vendor-released patch: upgrade Tamery to 0.99.0 or later, which is the first fixed version per the description and the VulnCheck advisory. The corresponding upstream change is commit 76e75a9569f31405751a63048bae076f500c1c2c (https://github.com/wannabespace/tamery/commit/76e75a9569f31405751a63048bae076f500c1c2c), and the defect is tracked in issue https://github.com/wannabespace/tamery/issues/601. Patch availability is confirmed by the vendor, so deployments on 0.26.1 through 0.98.x should be inventoried and moved to 0.99.0; no vendor-documented workaround or compensating control is provided in the available references, and self-hosted deployments still on a pre-0.99.0 build carry the same exposure through the cloud sync API. Additional detail on the cross-user write is published at https://hackmd.io/@hieuPenguinnn/conar-broken-ownership-cross-user-write and in the VulnCheck advisory.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in euvd
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Technical ContextAI · show details
CWE-639 (Authorization Bypass Through User-Controlled Key) in the oRPC-based cloud sync backend of Tamery, an AI chat client whose API lives in apps/api/orpc/routers/chats-messages/update.ts. The update handler on the chatsMessages collection accepts a client-supplied chatId and leaves it writable rather than rebinding it to the caller's own chat, so ownership of the destination record is never checked before the message parts and metadata are persisted. Because the key is taken directly from the request, knowing any target chat ID is sufficient to address that chat. The project's own repository guidance in the same fix commit reworks API conventions around create/remove procedures accepting single items rather than arrays and clarifies persisted-row and telemetry rules, and the vulnerable handler shape is still visible in the v0.32.0 tree referenced by the CVE. Reachability is network-based with low attack complexity, but the attacker must hold an authenticated account with a Pro subscription and must obtain a valid victim chat identifier. The skill is a write into the victim's AI chat history - integrity impact only, with no confidentiality or availability effect recorded by either the vendor's CVSS 4.0 vector or the independent CVSS 3.1 assessment.
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Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
PR:L because the attacker must be an authenticated Pro subscriber; integrity-only cross-user write gives I:L with C:N and A:N; network API with low complexity so AV:N/AC:L.
Primary rating from Vendor (VulnCheck).
CVSS VectorVendor: VulnCheck
DescriptionCVE.org
Tamery (formerly Conar) 0.26.1 before 0.99.0 contains an authorization bypass vulnerability in the cloud sync API chatsMessages.update handler, which leaves the client-supplied chatId writable. Authenticated Pro subscribers who know another user's chat ID can move messages with arbitrary parts and metadata into the victim's AI chat history.
Threat Intelligence Overview
NVD
CVE.org
EPSS
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
Exploit-DB