CVE-2026-58187Network attack vector

Denial of service via chunk-decoder buffer overrun

Published Jul 29, 2026 · Updated Jul 29, 2026

Out-of-bounds write in Apache Traffic Server's multiplexer plugin allows remote attackers to interrupt service via upstream input. Its chunk decoder writes beyond the allocated decode buffer while processing data returned by a multiplexed origin. Exploitation requires the multiplexer remap plugin to be configured; the resulting memory corruption is reported only as denial of service in 8.0.0 through 8.1.9, 9.0.0 through 9.2.14, and 10.0.0 through 10.1.3.

CVSS severity6.3
Medium
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Out-of-bounds write in Apache Traffic Server's multiplexer plugin allows remote attackers to interrupt service via upstream input. Its chunk decoder writes beyond the allocated decode buffer while processing data returned by a multiplexed origin. Exploitation requires the multiplexer remap plugin to be configured; the resulting memory corruption is reported only as denial of service in 8.0.0 through 8.1.9, 9.0.0 through 9.2.14, and 10.0.0 through 10.1.3.

The record

CVE
CVE-2026-58187
Published
Jul 29, 2026
Updated
Jul 29, 2026
Vendor
The Apache Software Foundation
Product
Apache Traffic Server
Classifications
CWE-787, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 29, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 29, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=10.0.0 <=10.1.3
  2. Affected versionversion=8.0.0 <=8.1.9
  3. Affected versionversion=9.0.0 <=9.2.14

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Traffic Serverversion=10.0.0 <=10.1.3; version=8.0.0 <=8.1.9; version=9.0.0 <=9.2.14

Published CVSS scores

6.3Apache Software FoundationCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
3.7Apache Software FoundationCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
7.5NIST National Vulnerability DatabaseCVSS: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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-787Out-of-bounds Write
T1499Endpoint Denial of Service

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo