---
id: CVE-2026-47783
title: >-
  In memcached before 1.6.42, username data for SASL password database
  authentication has a timing side channel because a loop exits as soon as a
  valid username is found by sasl_server_userdb_checkpass.
summary: >-
  In memcached before 1.6.42, username data for SASL password database
  authentication has a timing side channel because a loop exits as soon as a
  valid username is found by sasl_server_userdb_checkpass.
severity: high
cvss: 8.1
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-208
vendor: memcached
product: memcached
affected:
  - memcached < 1.6.42
patched:
  - memcached 1.6.42
published: '2026-05-20'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T13:18:29.257'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-47783'
references:
  - url: >-
      https://github.com/memcached/memcached/commit/d13f282b4bce33a9c33b8a1bbf07f12114160fed
    label: cve@mitre.org
  - url: 'https://github.com/memcached/memcached/compare/1.6.41...1.6.42'
    label: cve@mitre.org
  - url: 'https://github.com/memcached/memcached/wiki/ReleaseNotes1642'
    label: cve@mitre.org
  - url: 'https://access.redhat.com/errata/RHSA-2026:27842'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:27862'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/security/cve/CVE-2026-47783'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2480089'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-47783.json
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-47783'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-47783'
  - url: 'https://access.redhat.com/errata/RHSA-2026:63224'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.01264
epssPercentile: 0.67925
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-05-20T12:49:50.253452Z'
ingestedAt: '2026-09-18T12:40:48.889Z'
---

## Overview

In memcached before 1.6.42, username data for SASL password database authentication has a timing side channel because a loop exits as soon as a valid username is found by sasl_server_userdb_checkpass.

## Affected

- `memcached < 1.6.42`

## Remediation

Upgrade past the affected range:

- `memcached 1.6.42`

## Vendor advisories

- **RHSA-2026:27842** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10) · released 2026-06-22 · [advisory](https://access.redhat.com/errata/RHSA-2026:27842)
- **RHSA-2026:27862** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9) · released 2026-06-22 · [advisory](https://access.redhat.com/errata/RHSA-2026:27862)
- **Red Hat VEX** · Important · affected: Red Hat Hardened Images · no fix planned: Red Hat Hardened Images · updated 2026-09-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-47783.json)
- **RHSA-2026:63224** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-09-03 · [advisory](https://access.redhat.com/errata/RHSA-2026:63224)