High [CVE-2026-76763] Io.smallrye/smallrye-graphql: smallrye graphql: unauthenticated denial of service via large exponent float literals
This high-severity Red Hat Linux advisory covers CVE-2026-76763 affecting Red Hat build of Quarkus.
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Summary
A flaw was found in SmallRye GraphQL. The number scalar coercion for BigInteger does not properly validate the magnitude of float or string inputs.
An unauthenticated remote attacker can exploit this by sending a GraphQL query containing a large exponent float literal. This can lead to the allocation of extremely large BigInteger objects, causing CPU exhaustion or an OutOfMemoryError, resulting in a denial of service.
This flaw is rated as Important. This can lead to CPU exhaustion or an OutOfMemoryError, as the parsing occurs before authorization and affects commonly used data types like Long or BigInteger.
Red Hat severity: Important — CVSS 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-1284.
Affected Red Hat products: Red Hat build of Quarkus. Red Hat does not currently list a fixing RHSA for this CVE.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
Mitigation checklist
- To mitigate this issue, applications exposing SmallRye GraphQL endpoints should implement validation and bounding of the precision or exponent for incoming numeric literals before they reach scalar coercion. Additionally, limiting the JVM heap size can help constrain the impact of OutOfMemoryError, though it will not prevent CPU exhaustion. Implementing rate-limiting or timeouts on the GraphQL endpoint can also reduce exposure. Using GraphQL variables instead of inline literals for numeric inputs is a safe alternative, as variables follow a secure parsing path.
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
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