CVE-2026-24458Network attack vector

Unauthenticated service interruption via unbounded password comparison

Published Mar 16, 2026 · Updated Mar 16, 2026

DoS in Mattermost 10.11.0 through 10.11.10, 11.2.0 through 11.2.2, and 11.3.0 allows remote attackers to interrupt service via long login passwords. The legacy bcrypt CompareHashAndPassword path passes a multi-megabyte login password into password comparison without first enforcing PasswordMaxLengthBytes. No account or user interaction is required; repeated oversized login requests exhaust server CPU and memory and interrupt availability.

CVSS severity7.5
High
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

DoS in Mattermost 10.11.0 through 10.11.10, 11.2.0 through 11.2.2, and 11.3.0 allows remote attackers to interrupt service via long login passwords. The legacy bcrypt CompareHashAndPassword path passes a multi-megabyte login password into password comparison without first enforcing PasswordMaxLengthBytes. No account or user interaction is required; repeated oversized login requests exhaust server CPU and memory and interrupt availability.

The record

CVE
CVE-2026-24458
Published
Mar 16, 2026
Updated
Mar 16, 2026
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-770, T1499.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 16, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.11.0 <=10.11.10
  2. Affected versionversion=11.2.0 <=11.2.2
  3. Affected versionversion=11.3.0 <=11.3.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mattermost · Mattermostversion=10.11.0 <=10.11.10; version=11.2.0 <=11.2.2; version=11.3.0 <=11.3.0

Published CVSS scores

7.5Mattermost, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.002Service Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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