RHSA-2026:8753
Vulnerability from csaf_redhat - Published: 2026-04-17 11:29 - Updated: 2026-04-20 21:35Summary
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
Severity
Important
Notes
Topic: An update for Red Hat Hardened Images RPMs is now available.
Details: This update includes the following RPMs:
valkey:
* valkey-9.0.3-1.2.hum1 (aarch64, x86_64)
* valkey-compat-redis-9.0.3-1.2.hum1 (noarch)
* valkey-compat-redis-devel-9.0.3-1.2.hum1 (noarch)
* valkey-devel-9.0.3-1.2.hum1 (aarch64, x86_64)
* valkey-doc-9.0.3-1.2.hum1 (noarch)
* valkey-rdma-9.0.3-1.2.hum1 (aarch64, x86_64)
* valkey-9.0.3-1.2.hum1.src (src)
Terms of Use: This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Red Hat Inc. and provide a link to the original.
A flaw was found in Valkey, a distributed key-value database. A malicious actor with access to the Valkey clusterbus port can exploit an input validation vulnerability by sending a specially crafted invalid clusterbus packet. This lack of validation for clusterbus ping extension packets can lead to an out-of-bounds read. Consequently, this may cause the system to crash, resulting in a Denial of Service (DoS).
7.5 (High)
Vendor Fix
For details on how to apply this update, which includes the changes described in this advisory, refer to:
https://images.redhat.com/
https://access.redhat.com/errata/RHSA-2026:8753
Workaround
To mitigate this issue, restrict network access to the Valkey cluster bus port. Configure network access control lists (ACLs) or firewall rules to ensure that only trusted hosts can connect to the cluster bus port. This limits the attack surface by preventing unauthorized actors from sending malicious clusterbus packets.
References
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"cve": "CVE-2026-21863",
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"name": "Out-of-bounds Read"
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"discovery_date": "2026-02-23T21:03:12.281522+00:00",
"ids": [
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"notes": [
{
"category": "description",
"text": "A flaw was found in Valkey, a distributed key-value database. A malicious actor with access to the Valkey clusterbus port can exploit an input validation vulnerability by sending a specially crafted invalid clusterbus packet. This lack of validation for clusterbus ping extension packets can lead to an out-of-bounds read. Consequently, this may cause the system to crash, resulting in a Denial of Service (DoS).",
"title": "Vulnerability description"
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"text": "valkey: Valkey: Denial of Service via invalid clusterbus packet",
"title": "Vulnerability summary"
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"text": "This issue is rated High severity by Red Hat Product Security, because Valkey is commonly deployed as a network-accessible service or embedded within applications that accept remote input over standard network interfaces. In such environments, a remote attacker can trigger the vulnerability by sending specially crafted data to the service. Successful exploitation results in a service crash, leading to a denial-of-service condition. Although no confidentiality or integrity impacts are observed, the ability to repeatedly crash the service over the network justifies a High availability impact rating.\n\nThis vulnerability affects Valkey deployments where the cluster bus connection is exposed.",
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"Red Hat Hardened Images:valkey-main@noarch",
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{
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"attackVector": "NETWORK",
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"baseScore": 7.5,
"baseSeverity": "HIGH",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
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"title": "valkey: Valkey: Denial of Service via invalid clusterbus packet"
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}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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