Critical Security Update for memcached: Mitigating Username Enumeration Vulnerability
Summary
ALSA-2026:27842: Important: memcached security update. Affects memcached versions < 1.6.23-7.el10_2.1. Fixed in 1.6.23-7.el10_2.1. How to fix ↓
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Background
memcached is a high-performance, distributed memory object caching system designed to speed up dynamic web applications by reducing database load. It is widely used in various web applications to enhance performance and scalability. However, it is essential to maintain its security to prevent potential exploitation, as vulnerabilities can lead to unauthorized access or data leakage.
Vulnerability Detail
The vulnerability identified as CVE-2026-47783 allows for username enumeration through a timing side channel in memcached. This means that an attacker could potentially determine valid usernames by measuring the response times of the server to specific requests. Such an attack could lead to unauthorized access or further exploitation of the system, making it critical to address this issue promptly.
How To Fix
Minimum fixed version
1.6.23-7.el10_2.1
This is the first release that contains the fix.
sudo dnf update memcachedTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary measure, you can implement rate limiting on your memcached server to mitigate the risk of timing attacks. This can be done by configuring your application to limit the number of requests made to the memcached server within a specific timeframe.
Conclusion
The memcached security update addresses a critical vulnerability that could allow for username enumeration through timing attacks. It is crucial for users to update their memcached and memcached-selinux packages to the latest patched versions to ensure the security of their applications. Additionally, implementing temporary workarounds can help mitigate risks until the update is applied.
See every vulnerability recorded for memcached →
FAQ
CVE-2026-47783 is a security vulnerability in memcached that allows for username enumeration via a timing side channel.
If exploited, this vulnerability could allow attackers to identify valid usernames, potentially leading to unauthorized access to user accounts.
You should immediately update to the patched version 1.6.23-7.el10_2.1 to mitigate the risk associated with this vulnerability.
Yes, you can use Vulert's playground at Vulert Scanner to check if your application is affected by this vulnerability without needing to sign up.
Vulert is a tool that monitors and alerts in real-time for open-source vulnerabilities in software using just a manifest file like package-lock.json.
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