CVE-2023-32731
highpriority · track · 30EPSS 0.005 · 42 %ileDEEURUUSEPSS · scored 2026-10-27
When gRPC HTTP2 stack raised a header size exceeded error, it skipped parsing the rest of the HPACK frame. This caused any HPACK table mutations to also be skipped, resulting in a desynchronization of HPACK tables between sender and receiver. If leveraged, say, between a proxy and a backend, this could lead to requests from the proxy being interpreted as containing headers from different proxy clients - leading to an information leak that can be used for privilege escalation or data exfiltration. We recommend upgrading beyond the commit contained in https://github.com/grpc/grpc/pull/33005 https://github.com/grpc/grpc/pull/33005
remediations
Vendor fix, mitigation, or workaround guidance, as published by each source.
A vendor fix is available.
- Fixedphoenix_contact_psirt
Update to the latest 2024.0.6 LTS Firmware Release. PHOENIX CONTACT recommends to always use an up-to-date version of the PLCnext Engineer.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 5.3–7.5
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (26)
Products and version ranges known to be affected.
advisories (3)
Vendor and ecosystem advisories describing this.
- VDE-2024-073Phoenix Contact: Multiple Vulnerabilities in PLCnext Firmware2024-12-09csaf · phoenix_contact_psirtDE
Multiple Linux component vulnerabilities fixed in latest PLCnext Firmware release 2024.0.6 LTS
- GHSA-cfgp-2977-2fmmConnection confusion in gRPC2023-07-05ghsa · osvUS
When gRPC HTTP2 stack raised a header size exceeded error, it skipped parsing the rest of the HPACK frame. This caused any HPACK table mutations to also be skipped, resulting in a desynchronization of HPACK tables between sender and receiver. If leveraged, say, between a proxy and a backend, this could lead to requests from the proxy being interpreted as containing headers from different proxy clients - leading to an information leak that can be used for privilege escalation or data exfiltration.
- PYSEC-2026-1427Connection confusion in gRPC2026-07-07vendor · osvUS
When gRPC HTTP2 stack raised a header size exceeded error, it skipped parsing the rest of the HPACK frame. This caused any HPACK table mutations to also be skipped, resulting in a desynchronization of HPACK tables between sender and receiver. If leveraged, say, between a proxy and a backend, this could lead to requests from the proxy being interpreted as containing headers from different proxy clients - leading to an information leak that can be used for privilege escalation or data exfiltration.
also known as (7)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (10)
External citations — patches, advisories, analysis.
- https://access.redhat.com/security/cve/cve-2023-32731cnnvd
- https://cxsecurity.com/cveshow/CVE-2023-32731/cnnvd
- https://github.com/grpc/grpc/pull/32309cnnvd
- https://github.com/grpc/grpc/pull/33005cnnvd
- https://www.auscert.org.au/bulletins/ESB-2023.5125cnnvd
- https://www.auscert.org.au/bulletins/ESB-2023.7226cnnvd
- https://github.com/grpc/grpc/pull/32309enisa_euvd
- https://github.com/grpc/grpc/pull/33005enisa_euvd
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