GraphQL-core has denial of service via memory leak in aborted validations

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2026-119286: 0.42% estimated exploitation activity in the next 30 days; percentile 36.51 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary When a validation was aborted because the document contained more errors than allowed by `max_errors` (100 by default), `validate()` raised a single module-level `ValidationAbortedError` instance. Python appends the frames of every `raise` to the existing `traceback` of an exception that is raised again, so every aborted validation extended the traceback of this shared error. That traceback kept the frames, and with them the document, the validation context and all errors of every aborted validation, alive for the lifetime of the process.

Details Any client can trigger an aborted validation by sending a small document with more than 100 validation errors, e.g. 101 unknown fields. No authentication is required, and since validation runs before execution, depth limiters and complexity analyzers do not prevent it. Each such request permanently retained about 124 KiB on CPython 3.12, without an upper limit, so memory grew with every request until the process was…

Published by the source

30 Oct 2026, 22:58 UTC

Last modified by the source

30 Oct 2026, 23:15 UTC

Source last checked

31 Oct 2026, 06:15 UTC

1. Revision 2 · amended · 31 Oct 2026

   Amended from osv record GHSA-mpqx-q82w-9x46

2. Revision 1 · created · 30 Oct 2026

   Published from ghsa record GHSA-mpqx-q82w-9x46

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# Patch Next advisory brief: CVE-2026-119286

Advisory: GraphQL-core has denial of service via memory leak in aborted validations
IDs: CVE-2026-119286, GHSA-mpqx-q82w-9x46
Record: https://patchnext.com/advisories/cve-2026-119286 (revision 2, source checked 31 Oct 2026, 06:15 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: graphql-core 3.3.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI graphql-core: affected >= 3.3.0a3, < 3.3.1; fixed in 3.3.1

## Suggested inspection (read-only)
- `python -m pip show graphql-core`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on graphql-core.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-mpqx-q82w-9x46 (GitHub-reviewed advisory GHSA-mpqx-q82w-9x46 lists affected ranges: PyPI graphql-core >=3.3.0a3 <3.3.1)
- Verified: https://osv.dev/vulnerability/GHSA-mpqx-q82w-9x46 (OSV record GHSA-mpqx-q82w-9x46 lists affected ranges: PyPI graphql-core >=3.3.0a3 <3.3.1 (fixed))

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