EUVD-2026-50218
GHSA-2w9p-8x38-7x8f
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessReach ATS TLS listener over network
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DeliverySend ClientHello with crafted SNI
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ExploitCertifier plugin generates cert from SNI
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ExecutionAttacker obtains attacker-defined signed certificate
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ImpactAbuse forged cert identity/trust
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A07:2025 - Authentication Failures
ASVS 5.0
V12 - Secure Communication Certificate validation
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| Exploitation Conditions | Exploitation requires the target Apache Traffic Server to have the certifier plugin loaded and enabled for dynamic certificate generation - this is the AT:P precondition and is not ATS's default configuration. Given that plugin is active, the attacker only needs to reach the TLS listener over the network and supply an arbitrary client-controlled SNI in the TLS handshake; no authentication (PR:N) and no user interaction (UI:N) are required. The primary limiting factor is the non-default plugin deployment: installations that do not use the certifier plugin are not exploitable regardless of version. |
| Impact | The vendor CVSS 4.0 vector (AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:H) scores 8.4 and signals network-reachable, low-complexity, unauthenticated exploitation with high integrity and availability impact but only low confidentiality impact - consistent with a certificate-integrity flaw rather than data theft. The key moderating signal is AT:P (Attack Requirements: Present), meaning exploitation depends on a specific precondition: the certifier plugin must be deployed and enabled, which is not the default ATS configuration. There is no CISA KEV listing and no POC referenced, so this is not confirmed actively exploited and no public exploit is identified. EPSS data was not provided and cannot be cited. The realistic priority is high for the subset of operators running the certifier plugin (dynamic-cert CDN/edge setups) and low for the majority of ATS installs that do not load it; defenders should first determine whether the plugin is in use before treating this as urgent. |
| Exploit ScenarioDerived | An attacker connects to an ATS instance running the certifier plugin and presents a crafted SNI value in the TLS ClientHello, causing the plugin to generate and sign a certificate bearing an identity the attacker chose. The attacker leverages that attacker-influenced certificate to misrepresent trust or disrupt certificate handling on the proxy. No public exploit is identified at time of analysis, and the network/low-complexity vector means the handshake manipulation requires no authentication once the plugin is reachable. |
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Alert meAnalysisAIv3 – Jul 29, 2026
Improper certificate generation in the Apache Traffic Server certifier plugin lets remote attackers dictate the contents of dynamically minted TLS certificates by controlling the client SNI value, affecting ATS 8.0.0-8.1.9, 9.0.0-9.2.14, and 10.0.0-10.1.3. Because the plugin trusts attacker-supplied SNI to drive certificate creation (CWE-295), an unauthenticated remote party can influence which identities the proxy vouches for, undermining TLS trust. No public exploit identified at time of analysis, though the vendor-scored CVSS 4.0 base is 8.4 (high).
Earlier versions of this analysis (2)
Improper certificate generation in the Apache Traffic Server certifier plugin lets remote unauthenticated clients dictate the contents of dynamically generated TLS certificates through the client-supplied SNI value, affecting ATS 8.0.0-8.1.9, 9.0.0-9.2.14, and 10.0.0-10.1.3. Because the plugin trusts attacker-controlled SNI when minting certificates, an attacker can influence which identities ATS vouches for, undermining the integrity and availability of the TLS termination layer. No public exploit identified at time of analysis and this CVE is not listed in CISA KEV, but the vendor (Apache) has confirmed the flaw and shipped fixes.
Certificate forgery in Apache Traffic Server's certifier plugin allows unauthenticated remote attackers to cause the proxy to generate TLS certificates for arbitrary hostnames by supplying a crafted SNI value in a TLS ClientHello, enabling man-in-the-middle attacks against clients whose trust stores contain the ATS proxy CA. All three major release branches are affected: 8.0.0-8.1.9, 9.0.0-9.2.14, and 10.0.0-10.1.3, with vendor-released patches available at 9.2.15 and 10.1.4. No public exploit code and no CISA KEV listing have been identified at time of analysis, but the attack requires only a standard TLS client and network access to the proxy, making exploitation trivially reproducible.
RemediationAI
Vendor-released patch: upgrade to Apache Traffic Server 9.2.15 or 10.1.4, which fix the issue per the Apache advisory (https://lists.apache.org/thread/5prl9glcm9g2swnq9hqxvnokylm1gr6d); note the 8.x line has no listed fixed release, so 8.0.0-8.1.9 users should migrate to a fixed 9.2.x or 10.1.x build. If immediate patching is not possible, the most effective compensating control is to disable or unload the certifier plugin from remap/plugin configuration, since the vulnerability only manifests when that plugin generates certificates from client SNI; the trade-off is loss of dynamic on-the-fly certificate generation, requiring pre-provisioned certificates instead. Where the plugin must stay enabled, restrict which clients and SNI values can reach the TLS listener via network ACLs or an upstream filter to limit attacker control over SNI, accepting that this narrows legitimate client reach.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in euvd
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Technical ContextAI · show details
Apache Traffic Server is a high-performance forward/reverse HTTP caching proxy. The optional 'certifier' plugin performs on-the-fly TLS certificate generation and signing so ATS can terminate or bridge TLS for many hostnames without pre-provisioning each certificate. It keys certificate generation on the Server Name Indication (SNI) field presented by the connecting client during the TLS handshake. The flaw is a CWE-295 Improper Certificate Validation issue: the client-supplied SNI is attacker-controlled input, yet the plugin uses it directly as the basis for the certificate it generates, so an attacker chooses the subject/identity material that gets signed. The CPE cpe:2.3:a:apache_software_foundation:apache_traffic_server confirms the affected component is the ATS product itself, specifically deployments that load the certifier plugin.
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Severity by source
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:H/SC:N/SI:N/SA:N
Network-reachable and unauthenticated (AV:N/PR:N), but AC:H reflects the required non-default certifier plugin; impact is integrity/availability high with low confidentiality, matching a cert-generation flaw.
Primary rating from Vendor (apache).
CVSS VectorVendor: apache
Lifecycle Timeline
5DescriptionCVE.org
The Apache Traffic Server certifier plugin generates certificates based on attacker-controlled client SNI.
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
Apache Traffic Server's certificate generation feature can be manipulated by remote attackers to issue TLS certificates for fraudulent identities, compromising the encryption trust that protects sensitive communications flowing through the proxy. This allows attackers to intercept and decrypt data intended to be secure, affecting any organization using ATS 8.0.0-10.1.3. The vulnerability requires no authentication and poses a material risk to data confidentiality for all systems relying on these proxies.
No vendor-released patch identified at time of analysis. Interim mitigations: (1) enforce an allowlist restricting which domain identities the proxy may include in dynamically generated certificates; (2) log and alert on all certificate generation events to detect exploitation attempts; (3) implement network inspection to flag anomalous SNI-to-certificate patterns; (4) where applicable, require mutual TLS with pinned client certificates to reduce proxy trust dependency; (5) begin migration planning immediately for deployment of vendor patches upon release.
Threat Intelligence Overview
NVD
CVE.org
EPSS
Vulnrichment
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.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.
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