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🛡️ CVE-2023-32731 — grpc

🟠 CVSS 8.0 — High ✅ No Known Exploit CWE-440 OSV
8.0
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

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

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is high, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity none, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: High — the attacker first has to win a race, learn a secret or otherwise prepare the target.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: None.
  • Availability impact: High — total loss, or loss the attacker controls.

Weakness class

CVE-2023-32731 is classified as CWE-440: Expected Behavior Violation. A feature, API, or function does not perform according to its specification.

Affected software

CVE-2023-32731 is recorded against 3 packages.

  • grpc (from 1.54.0 up to 1.54.2)
  • grpcio (from 1.54.0 up to 1.54.2)
  • io.grpc:grpc-protobuf (from 1.54.0 up to 1.54.2)

Timeline and source

Published on 5 July 2023 and last revised on 7 July 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from OSV.

References

nvd.nist.gov (Advisory)
github.com (Web)
github.com (Web)
github.com (Web)
github.com (Web)
github.com (Web)
github.com (Web)
github.com (Web)
github.com (Web)

Other advisories for this package

grpc has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-440: Expected Behavior Violation) in other software:

CVE-2023-32731 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity HIGH
CVSS Score 8.0
CVSS Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H
CWE CWE-440
Public Exploit ✅ No
Source OSV
Published 2023-07-05
Updated 2026-08-20
Modified 2026-07-07

Affected Packages

Software From version Fixed in
grpc 1.54.0 1.54.2
grpcio 1.54.0 1.54.2
io.grpc:grpc-protobuf 1.54.0 1.54.2

Similar Threats

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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