How severe is CVE-2026-23897?

CVE-2026-23897 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-23897 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-23897?

CVE-2026-23897 affects Apollographql Apollo Server. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-23897?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-23897 have an EU (EUVD) identifier?

Yes. CVE-2026-23897 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-5364.

When was CVE-2026-23897 published?

CVE-2026-23897 was published on 2026-02-04 and last updated on 2026-06-17.

CVE-2026-23897

CVE-2026-23897 is a high-severity vulnerability in Apollographql Apollo Server with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-1333.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (46th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-5364
Weakness: CWE-1333
Affected product: Apollographql Apollo Server
Published: 2026-02-04
Last modified: 2026-06-17

Description

Apollo Server is an open-source, spec-compliant GraphQL server that's compatible with any GraphQL client, including Apollo Client. In versions from 2.0.0 to 3.13.0, 4.2.0 to before 4.13.0, and 5.0.0 to before 5.4.0, the default configuration of startStandaloneServer from @apollo/server/standalone is vulnerable to denial of service (DoS) attacks through specially crafted request bodies with exotic character set encodings. This issue does not affect users that use @apollo/server as a dependency for integration packages, like @as-integrations/express5 or @as-integrations/next, only direct usage of startStandaloneServer.

Frequently asked questions

What is CVE-2026-23897?: Apollo Server is an open-source, spec-compliant GraphQL server that's compatible with any GraphQL client, including Apollo Client. In versions from 2.0.0 to 3.13.0, 4.2.0 to before 4.13.0, and 5.0.0 to before 5.4.0, the default configuration of startStandaloneServer from @apollo/server/standalone is vulnerable to denial of service (DoS) attacks through specially crafted request bodies with exotic character set encodings. This issue does not affect users that use @apollo/server as a dependency for integration packages, like @as-integrations/express5 or @as-integrations/next, only direct usage of startStandaloneServer.
How severe is CVE-2026-23897?: CVE-2026-23897 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-23897 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-23897?: CVE-2026-23897 affects Apollographql Apollo Server. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-23897?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-23897 have an EU (EUVD) identifier?: Yes. CVE-2026-23897 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-5364.
When was CVE-2026-23897 published?: CVE-2026-23897 was published on 2026-02-04 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:apollographql:apollo_server:*:*:*:*:*:*:*:*

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