CVE-2021-34824Network attack vector

TLS credential disclosure via cross-namespace XDS cache access

Published Jun 29, 2021 · Updated Aug 4, 2024

Access control failure in Istio 1.8.x, 1.9.0 through 1.9.5, and 1.10.0 through 1.10.1 allows remote authenticated users to read TLS credentials. Istiod serves credentialName requests from its XDS cache without enforcing the requesting gateway or workload namespace, exposing cached TLS certificates and private keys. The cluster must use credentialName in a Gateway or DestinationRule with XDS caching enabled; disclosure is limited to credentials cached by Istiod.

CVSS severity9.1
Critical
EPSS probability1.99%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Access control failure in Istio 1.8.x, 1.9.0 through 1.9.5, and 1.10.0 through 1.10.1 allows remote authenticated users to read TLS credentials. Istiod serves credentialName requests from its XDS cache without enforcing the requesting gateway or workload namespace, exposing cached TLS certificates and private keys. The cluster must use credentialName in a Gateway or DestinationRule with XDS caching enabled; disclosure is limited to credentials cached by Istiod.

The record

CVE
CVE-2021-34824
Published
Jun 29, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1552.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 29, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.5NIST NVDAV:N/AC:L/Au:S/C:P/I:P/A:P
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
9.1IstioCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1552.004Unsecured Credentials: Private Keys

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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