7.5

CVE-2023-32731: Information leak in gRPC

Modified
AliasesGHSA-cfgp-2977-2fmmPYSEC-2026-1427UBUNTU-CVE-2023-32731
Published 09-06-2023Last modified 26-09-2024

Vulnerability summary

CVE-2023-32731 is a high (CVSS 7.5) Expected Behavior Violation vulnerability in google grpc. EPSS estimates a 0.50% chance of exploitation in the next 30 days, higher than 42.7% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 7.4 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 0% (FIRST, 03-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
7.5/10
010
High · v3.1 (NVD)
EPSS score
0.50%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 3 · Related 6
OPENSUSE-SU-2026:11926-1RHSA-2024:10761SUSE-SU-2024:0573-1CGA-3C2Q-4QQC-238JCGA-8CF4-MMM4-2RR5CGA-GGP4-VW2X-23HX

Timeline

  1. 09-06-2023
    PublishedVulnerability first disclosed.
  2. 26-09-2024
    Last modifiedVulnerability information updated.

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

CVSS metrics

8 scores · 8 sources · 1 version

EPSS trend

Probability

0.50%

Chance of exploitation in the next 30 days

Percentile

43%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.50% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard1 product
  • wavefront-proxy< 13.4-r1
Google1 product
  • grpc≥ 1.53, ≤ 1.54
Grpc1 product
  • grpc≥ 1.53.0, < 1.55.0
Io.grpc1 product
  • grpc-protobuf≥ 1.53.0, < 1.53.1 | ≥ 1.54.0, < 1.54.2
PyPI1 product
  • grpcio≥ 1.53.0, < 1.53.1 | ≥ 1.54.0, < 1.54.2
RubyGems1 product
  • grpc≥ 1.53.0, < 1.53.1 | ≥ 1.54.0, < 1.54.2
Ubuntu1 product
  • grpcAll versions (No fix recorded)
Wolfi1 product
  • wavefront-proxy< 13.4-r1

8 vendors · 8 products

References

15 links
Show all 15 references