CyberSecBulletin
CVE-2026-41920NVD status: Analyzed

Apache Traffic Server: Improper Access Control

Published Updated By the CyberSecBulletin desk

CVE-2026-41920 is a critical-severity improper access control vulnerability in Apache Traffic Server from Apache, with a CVSS 3.1 base score of 9.3 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Apache Traffic Server versions: 9.0.0 through 9.1.14; 10.0.0 through 10.1.3. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.53% chance of exploitation within 30 days, which is low compared with other CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update Traffic Server to 9.2.15 or 10.1.4, whichever matches your release line, or a later version.
  2. Read the advisory on lists.apache.org for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
ApacheApache Traffic Server9.0.0 through 9.1.14; 10.0.0 through 10.1.3Not stated
ApacheTraffic Server9.0.0 up to, but not including, 9.2.15; 10.0.0 up to, but not including, 10.1.49.2.15, 10.1.4

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
ChangedThe attack can reach beyond the vulnerable component into other systems.
Confidentiality
LowSome restricted data can be read.
Integrity
HighData or code can be modified at will.
Availability
NoneAvailability is not affected.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:N. Scored by CNA (apache.org).

Scoring systemScoreSeverityScored by
CVSS 4.07.0HighCNA (apache.org)
CVSS 3.19.3CriticalCNA (apache.org)

Official description

Improper Access Control vulnerability in Apache Traffic Server. This issue affects Apache Traffic Server: from 9.0.0 through 9.1.14, from 10.0.0 through 10.1.3. Users are recommended to upgrade to version 9.1.15 or 10.1.4, which fixes the issue.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Access Control

The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.

How developers prevent this class of flaw

  • Very carefully manage the setting, management, and handling of privileges. Explicitly manage trust zones in the software.
  • Compartmentalize the system to have safe areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.

More Improper Access Control vulnerabilities (CWE-284)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in Apache Traffic Server

All Apache Traffic Server vulnerabilities

Recent Improper Access Control vulnerabilities

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