CVE-2023-32732Network attack vector

Connection termination via malformed binary metadata

Published Jun 9, 2023 · Updated Feb 13, 2025

Denial of service in gRPC 1.53 before 1.54 allows remote attackers to terminate a proxied server connection using malformed binary metadata. The HTTP/2 metadata parser treats a base64 decoding failure in a -bin-suffixed header as a transport error and closes the entire connection instead of canceling only the affected stream. The request must traverse an HTTP/2 proxy that accepts the malformed header; the result is a connection-level service interruption.

CVSS severity5.3
Medium
EPSS probability0.53%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in gRPC 1.53 before 1.54 allows remote attackers to terminate a proxied server connection using malformed binary metadata. The HTTP/2 metadata parser treats a base64 decoding failure in a -bin-suffixed header as a transport error and closes the entire connection instead of canceling only the affected stream. The request must traverse an HTTP/2 proxy that accepts the malformed header; the result is a connection-level service interruption.

The record

CVE
CVE-2023-32732
Published
Jun 9, 2023
Updated
Feb 13, 2025
Vendor
gRPC
Product
gRPC
Classifications
CWE-440, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 9, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.53 <1.54

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

gRPC · gRPCversion=1.53 <1.54

Published CVSS scores

5.3Google LLCCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-440Expected Behavior Violation
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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