# CVE-2026-110802: Altair: DOM-based XSS via attacker-controlled script URLs in the iframe sandbox

Status: published. Published: 2026-11-05. Updated: 2026-11-10.

Altair is a GraphQL client for all platforms. From 7.2.4 until 8.5.8, packages/altair-iframe-sandbox/src/main.ts reads plugin_sandbox_opts from the iframe-sandbox query string and passes attacker-controlled scriptUrls to injectScript() in packages/altair-core/src/utils/inject.ts, which creates script elements in the page. The intended parent iframe flow places the page in an iframe with sandbox allow-scripts and without allow-same-origin, but direct navigation to a crafted iframe-sandbox URL omits that isolation and executes the supplied script in the origin serving Altair. Exploitation requires a victim to open the crafted URL, and the resulting script can access script-readable storage and make same-origin requests according to the deployment's authentication and cookie controls. This issue is fixed in version 8.5.8.

## Remediation

- fix: altair-static (npm): GitHub reports patched versions 8.5.8. Check the advisory for the affected release branch. (source: GitHub GHSA-752m-7p75-49gf) — https://github.com/altair-graphql/altair/security/advisories/GHSA-752m-7p75-49gf
- fix: altair-express-middleware (npm): GitHub reports patched versions 8.5.8. Check the advisory for the affected release branch. (source: GitHub GHSA-752m-7p75-49gf) — https://github.com/altair-graphql/altair/security/advisories/GHSA-752m-7p75-49gf
- fix: altair-koa-middleware (npm): GitHub reports patched versions 8.5.8. Check the advisory for the affected release branch. (source: GitHub GHSA-752m-7p75-49gf) — https://github.com/altair-graphql/altair/security/advisories/GHSA-752m-7p75-49gf
- fix: altair-fastify-plugin (npm): GitHub reports patched versions 8.5.8. Check the advisory for the affected release branch. (source: GitHub GHSA-752m-7p75-49gf) — https://github.com/altair-graphql/altair/security/advisories/GHSA-752m-7p75-49gf

## Affected products and versions

- altair-graphql / altair: >= 7.2.4, < 8.5.8 (affected). Source: CNA: GitHub_M
- altair-graphql / altair-express-middleware: >= 7.2.4, < 8.5.8 (affected). Source: CNA: GitHub_M
- altair-graphql / altair-fastify-plugin: >= 7.2.4, < 8.5.8 (affected). Source: CNA: GitHub_M
- altair-graphql / altair-koa-middleware: >= 7.2.4, < 8.5.8 (affected). Source: CNA: GitHub_M
- altair-graphql / altair-static: >= 7.2.4, < 8.5.8 (affected). Source: CNA: GitHub_M
-  / altair-static (altair-static): 7.2.4 <=> 8.5.7 (affected, GitHub advisory range). Source: GitHub GHSA-752m-7p75-49gf
-  / altair-express-middleware (altair-express-middleware): 7.2.4 <=> 8.5.7 (affected, GitHub advisory range). Source: GitHub GHSA-752m-7p75-49gf
-  / altair-koa-middleware (altair-koa-middleware): 7.2.4 <=> 8.5.7 (affected, GitHub advisory range). Source: GitHub GHSA-752m-7p75-49gf
-  / altair-fastify-plugin (altair-fastify-plugin): 7.2.4 <=> 8.5.7 (affected, GitHub advisory range). Source: GitHub GHSA-752m-7p75-49gf

## Severity and prioritization

- CVSS 3.1: 6.1 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N; source: CNA: GitHub_M

- CVSS 3.1: 6.1 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N; source: NVD: security-advisories@github.com

- CISA KEV: No listing in collected sources

- EPSS: 0.22% as of 2026-11-09; percentile 12.72%

- SSVC: exploitation poc; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-79, CWE-829

## Exploit evidence

- exploit: https://github.com/altair-graphql/altair/security/advisories/GHSA-752m-7p75-49gf (ADP: CISA-ADP)

## References

- https://github.com/altair-graphql/altair/security/advisories/GHSA-752m-7p75-49gf (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/altair-graphql/altair/commit/53a19183ce11ca147bb990c355e14ecb1dd7cd3e (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/altair-graphql/altair/commit/bdf422bdaaaf3186170ba7f22e22c259072133d9 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/altair-graphql/altair/releases/tag/v8.5.8 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/altair-graphql/altair/security/advisories/GHSA-752m-7p75-49gf (ADP: CISA-ADP; exploit)

- https://github.com/altair-graphql/altair/commit/53a19183ce11ca147bb990c355e14ecb1dd7cd3e (security-advisories@github.com)

- https://github.com/altair-graphql/altair/commit/bdf422bdaaaf3186170ba7f22e22c259072133d9 (security-advisories@github.com)

- https://github.com/altair-graphql/altair/releases/tag/v8.5.8 (security-advisories@github.com)

- https://github.com/altair-graphql/altair/security/advisories/GHSA-752m-7p75-49gf (security-advisories@github.com)

- https://github.com/altair-graphql/altair/security/advisories/GHSA-752m-7p75-49gf (134c704f-9b21-4f2e-91b3-4a467353bcc0)

- https://github.com/altair-graphql/altair/security/advisories/GHSA-752m-7p75-49gf (GitHub Security Advisories; advisory)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-110802; retrieved 2026-11-10; source updated 2026-11-10

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-110802; retrieved 2026-11-10; source updated 2026-11-10

- GitHub Security Advisories: https://github.com/altair-graphql/altair/security/advisories/GHSA-752m-7p75-49gf; retrieved 2026-11-07; source updated 2026-10-16

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-110802; retrieved 2026-11-10; source updated Not reported

Revision: 628ab7f62c5403e239dabc25c28ad675f9c944ed78f555d19a836d969f6433d4

Canonical: https://y2.dev/cve/CVE-2026-110802

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