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Apache Traffic Server CVE-2026-58180

| EUVDEUVD-2026-50225 HIGH
Stack-based Buffer Overflow (CWE-121)
2026-07-29 apache GHSA-jxxq-f4qq-497f
8.2
CVSS 4.0 · Vendor: apache
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Reach ATS instance running txn_box
  2. Delivery
    Send oversized crafted HTTP request
  3. Exploit
    Overflow fixed-size stack buffer
  4. Execution
    Corrupt stack / return address
  5. Persist
    Crash Traffic Server process
  6. Impact
    Denial of service to clients

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Stack buffer bounds checking
MITRE ATT&CK

1 technique across 1 tactic: Execution

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Exploitation requires the target Apache Traffic Server to have the experimental txn_box plugin loaded and configured to process transactions - this is the concrete prerequisite, since the overflow lives in that plugin's handling of attacker-controlled request input and default ATS installations do not enable it. Once txn_box is active, no authentication or user interaction is needed (PR:N/UI:N) and the attack is delivered over the network (AV:N). The CVSS AT:P (attack requirement) flag signals that a specific condition beyond a plain request must hold - consistent with the input needing to reach and exceed the vulnerable buffer in the plugin's processing path. The chief limiting factor is therefore the non-default txn_box deployment; instances not running the plugin are not exposed.

Impact

The CVSS 4.0 base score of 8.2 (High) reflects AV:N (network), AC:L (low complexity), PR:N (no privileges) and UI:N (no user interaction), but crucially AT:P - a specific attack requirement must be met - and an impact set limited to VA:H with VC:N/VI:N (availability only, no data exposure or code integrity loss). This positions the vulnerability as a remotely triggerable denial-of-service rather than confirmed remote code execution, even though stack overflows can sometimes be escalated; neither the vendor advisory nor NVD claims code execution here. EPSS is not provided, the CVE is not in CISA KEV, and no POC is referenced, so real-world exploitation pressure is currently unproven. The decisive limiting factor is that the vulnerable txn_box plugin is experimental and not enabled in default ATS deployments, which sharply narrows the exposed population despite the network attack vector. Net assessment: patch promptly on any ATS instance running txn_box, but the practical risk to default installations is low because the code path is not loaded.

Exploit ScenarioDerived

An attacker sends a crafted HTTP request whose fields exceed the size the txn_box plugin expects, overflowing a fixed-size stack buffer as the plugin processes the transaction. The corrupted stack causes the Traffic Server process to crash, dropping in-flight connections and denying service to legitimate users. No public exploit code is identified at time of analysis, and success depends on the target having the txn_box plugin loaded.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
No patch listed yet 0.4% exploitation probability (EPSS)

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AnalysisAIv2 – Jul 29, 2026

Denial of service in Apache Traffic Server (versions 8.0.0-8.1.9, 9.0.0-9.2.14, and 10.0.0-10.1.3) arises from a stack-based buffer overflow in the txn_box plugin, which copies attacker-controlled input onto the stack without adequate bounds checking. Remote attackers reaching an ATS instance that loads the txn_box transaction-manipulation plugin can crash the server process; the CVSS 4.0 vector (8.2) scores the impact as availability-only (VA:H) with no confidentiality or integrity loss. There is no public exploit identified at time of analysis and the issue is not listed in CISA KEV.

Earlier versions of this analysis (1)
v1 Jul 29, 2026 - 09:56 CVSS 7.5

Stack-based buffer overflow in the txn_box plugin of Apache Traffic Server allows remote unauthenticated attackers to crash the server via crafted input, causing denial of service. Affected versions span the 8.x, 9.x, and 10.x release lines with fixed versions available for the 9.x and 10.x branches. No public exploit or active exploitation has been identified at time of analysis; however, the zero-prerequisite network attack vector makes this a credible availability risk for any internet-facing ATS deployment running the txn_box plugin.

RemediationAI

Vendor-released patch: upgrade to Apache Traffic Server 9.2.15 or 10.1.4, which fix the overflow; the 8.x line is affected through 8.1.9 with no fixed 8.x release named in the advisory, so 8.x operators should migrate to a patched 9.2.x or 10.1.x build. If immediate upgrade is not possible, the most effective compensating control is to unload or disable the txn_box plugin in plugin.config/remap.config, since the vulnerable code path is only reachable when that experimental plugin is active - the trade-off is loss of any transaction-rewriting rules it provides. As a secondary measure, filter and constrain untrusted input reaching txn_box-processed transactions (for example via upstream WAF/reverse-proxy validation of request fields), accepting that this only reduces rather than removes exposure. Refer to the Apache advisory at https://lists.apache.org/thread/5prl9glcm9g2swnq9hqxvnokylm1gr6d for authoritative guidance.

Affected VersionsENISA

Apache Traffic Server 8.0.0 ≤8.1.9
Apache Traffic Server 9.0.0 ≤9.2.14
Apache Traffic Server 10.0.0 ≤10.1.3

Affected Packages

euvd apache_traffic_server no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

Apache Traffic Server is a high-performance caching HTTP forward/reverse proxy widely used at CDN and edge scale. The flaw resides in txn_box, an experimental ATS plugin that lets operators rewrite and manipulate transactions (headers, URLs, request/response fields) via a declarative configuration. The root cause is CWE-121 (stack-based buffer overflow): the plugin writes attacker-influenced data into a fixed-size stack buffer without validating its length, corrupting adjacent stack memory such as saved registers or the return address. Because txn_box processes live request data, hostile input arrives over the network path the proxy already serves. The CPE cpe:2.3:a:apache_software_foundation:apache_traffic_server:*:*:*:*:*:*:*:* identifies the ATS package itself; the vulnerable code path is only reachable when the txn_box plugin is deployed and configured.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (apache) PRIMARY 8.2 MEDIUM
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
vuln.today AI 5.9 MEDIUM

Network-reachable with no auth (AV:N/PR:N) but requires the non-default txn_box plugin and specific oversized input (AC:H); impact is availability-only DoS (A:H, C:N/I:N).

3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
4.0 AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (apache).

CVSS VectorVendor: apache

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
None
User Interaction
None
Vulnerable system: Confidentiality
None
Vulnerable system: Integrity
None
Vulnerable system: Availability
High
Subsequent system: Confidentiality
None
Subsequent system: Integrity
None
Subsequent system: Availability
None

Lifecycle Timeline

4
Analysis Updated
Jul 29, 2026 - 10:39 vuln.today
v2 - CVSS changed
Severity Changed
Jul 29, 2026 - 10:22 NVD
MEDIUM HIGH
CVSS changed
Jul 29, 2026 - 10:22 NVD
7.5 (MEDIUM) 8.2 (HIGH)
CVE Published
Jul 29, 2026 - 08:45 cve.org
MEDIUM 7.5

DescriptionCVE.org

The Apache Traffic Server txn_box plugin overflows the stack from attacker-controlled input.

This issue affects Apache Traffic Server: from 8.0.0 through 8.1.9, from 9.0.0 through 9.2.14, from 10.0.0 through 10.1.3.

Users are recommended to upgrade to version 9.2.15 or 10.1.4, which fix the issue.

Executive ViewAI

Why It Matters

Apache Traffic Server versions 8.0.0-10.1.3 contain a remotely exploitable denial-of-service vulnerability in the txn_box plugin that allows attackers to crash the server process without user interaction. No vendor patch is currently available, creating operational risk for any organization using ATS with this plugin enabled. Immediate action is required to limit attack surface or prepare for upgrade to patched versions when released.

Business Impact: High
Compensating Controls

Disable the txn_box plugin if transaction manipulation functionality is not operationally critical. Implement network-level access controls to restrict ATS inbound connections to trusted internal clients only, reducing remote attack surface. Deploy load-balancer or reverse-proxy failover to automatically redirect traffic if an ATS process crashes. Monitor syslog and ATS error logs for abnormal process termination events. Do not rely on these controls as permanent; prioritize vendor upgrade path as primary remediation.

Threat Intelligence Overview

EPSS Score
0.4%
Top 64% exploitable
Prevalence
Medium
ATS common at CDN/edge scale, but vulnerable txn_box plugin is non-default
Data Quality
5 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC No
EPSS 0.4%
Patch available No
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
Yes
Human Impact
High
Technical Impact
Partial

Priority Score

41
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +41
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

A stack-based buffer overflow occurs when a program writes more data to a buffer located on the stack than it was allocated to hold.

CVE-2026-111813 CRITICAL
10.0 Oct 21

Apache Traffic Server versions 8.0.1 through 8.1.11, 9.0.0 through 9.2.15, 10.0.0 through 10.1.4, and 10.2.0 ship an exp

CVE-2026-58161 CRITICAL
9.2 Jul 29

Remote denial of service in Apache Traffic Server (8.0.0-8.1.9, 9.0.0-9.2.14, 10.0.0-10.1.3) allows unauthenticated atta

CVE-2026-58154 CRITICAL
9.2 Jul 29

Out-of-bounds write and integer overflow in Apache Traffic Server's MIME and HTTP header parsing lets remote attackers c

CVE-2026-58155 CRITICAL
9.2 Jul 29

Request smuggling and policy bypass in Apache Traffic Server (branches 8.0.0-8.1.9, 9.0.0-9.2.14, and 10.0.0-10.1.3) ari

CVE-2026-111816 CRITICAL
9.2 Oct 21

Response-framing desync in Apache Traffic Server (8.0.0 through 8.1.11, 9.0.0 through 9.2.15, 10.0.0 through 10.1.4, and

CVE-2025-31699 CRITICAL
9.1 Oct 21

Request smuggling in Apache Traffic Server 8.0.0 through 8.1.11, 9.0.0 through 9.2.15, 10.0.0 through 10.1.4, and 10.2.0

CVE-2026-111804 HIGH
8.8 Oct 21

Unauthenticated remote attackers can drive HTTP transactions to completion against Apache Traffic Server instances that

CVE-2026-58151 HIGH
8.7 Jul 29

Denial of service in Apache Traffic Server 8.0.0-8.1.9, 9.0.0-9.2.14, and 10.0.0-10.1.3 lets remote unauthenticated atta

CVE-2026-111810 HIGH
8.7 Oct 21

Apache Traffic Server 9.2.15, 10.1.4, and 10.2.0 can be driven into a denial-of-service condition through log amplificat

CVE-2026-58188 HIGH
8.4 Jul 29

Out-of-bounds write and limit-bypass flaws in several experimental plugins shipped with Apache Traffic Server (8.0.0-8.1

CVE-2026-58162 HIGH
8.4 Jul 29

Improper certificate generation in the Apache Traffic Server certifier plugin lets remote attackers dictate the contents

CVE-2026-58164 HIGH
8.3 Jul 29

Memory corruption in Apache Traffic Server's remap configuration handling lets remote attackers trigger a use-after-free

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