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Vulnerability Assessment

Weakness
CWE
CWE-444
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V4 - API and Web Service HTTP request consistency
Impact

CVSS score of 4.2 (MEDIUM). Attack characteristics: network attack vector, high complexity, low privileges required, no user interaction not required.
Exploit ScenarioDerived

A remote attacker could manipulate HTTP request interpretation between frontend and backend servers by sending crafted requests to the affected application.
This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 8.4% exploitation probability (EPSS)

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AnalysisAI

A vulnerability was found in Apache HTTP Server 2.4.34 to 2.4.38. Rated medium severity (CVSS 4.2), this vulnerability is remotely exploitable. This HTTP Request/Response Smuggling vulnerability could allow attackers to manipulate HTTP request interpretation between frontend and backend servers.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Enforce strict HTTP parsing, normalize requests at proxy layer, use HTTP/2 end-to-end, reject ambiguous headers.

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Technical ContextAI · show details

This vulnerability is classified as HTTP Request/Response Smuggling (CWE-444), which allows attackers to manipulate HTTP request interpretation between frontend and backend servers. A vulnerability was found in Apache HTTP Server 2.4.34 to 2.4.38. When HTTP/2 was enabled for a http: host or H2Upgrade was enabled for h2 on a https: host, an Upgrade request from http/1.1 to http/2 that was not the first request on a connection could lead to a misconfiguration and crash. Server that never enabled the h2 protocol or that only enabled it for https: and did not set "H2Upgrade on" are unaffected by this issue. Affected products include: Apache Http Server, Canonical Ubuntu Linux, Fedoraproject Fedora, Opensuse Leap, Redhat Jboss Core Services.

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  • Exploit and PoC references, threat intelligence from 22 sources
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Severity by source

NVD PRIMARY 4.2 MEDIUM
AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
Low

DescriptionNVD

A vulnerability was found in Apache HTTP Server 2.4.34 to 2.4.38. When HTTP/2 was enabled for a http: host or H2Upgrade was enabled for h2 on a https: host, an Upgrade request from http/1.1 to http/2 that was not the first request on a connection could lead to a misconfiguration and crash. Server that never enabled the h2 protocol or that only enabled it for https: and did not set "H2Upgrade on" are unaffected by this issue.

Threat Intelligence Overview

EPSS Score
8.4%
Top 6% exploitable
Data Quality
2 sources
Confidence: Low
NVD CVE.org EPSS

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 MEDIUM
CISA KEV No
Public POC No
EPSS 8.4%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
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· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
No
Human Impact· derived
Medium

Priority Score

29
Low Medium High Critical
KEV: 0
EPSS: +8
CVSS: +21
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

HTTP Request Smuggling HIGH

HTTP request smuggling exploits inconsistencies in how front-end and back-end servers parse HTTP message boundaries.

Denial of Service MEDIUM

Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.

Affected Products (CPE)NVD

cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:esm:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:19.04:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:30:*:*:*:*:*:*:*
cpe:2.3:o:opensuse:leap:15.0:*:*:*:*:*:*:*
cpe:2.3:o:opensuse:leap:42.3:*:*:*:*:*:*:*
cpe:2.3:a:redhat:jboss_core_services:1.0:*:*:*:*:*:*:*
cpe:2.3:a:oracle:communications_session_report_manager:8.0.0:*:*:*:*:*:*:*
cpe:2.3:a:oracle:communications_session_report_manager:8.1.0:*:*:*:*:*:*:*
cpe:2.3:a:oracle:communications_session_report_manager:8.1.1:*:*:*:*:*:*:*
cpe:2.3:a:oracle:communications_session_report_manager:8.2.0:*:*:*:*:*:*:*
cpe:2.3:a:oracle:communications_session_route_manager:8.0.0:*:*:*:*:*:*:*
cpe:2.3:a:oracle:communications_session_route_manager:8.1.0:*:*:*:*:*:*:*
cpe:2.3:a:oracle:communications_session_route_manager:8.1.1:*:*:*:*:*:*:*
cpe:2.3:a:oracle:communications_session_route_manager:8.2.0:*:*:*:*:*:*:*
cpe:2.3:a:oracle:enterprise_manager_ops_center:12.3.3:*:*:*:*:*:*:*
cpe:2.3:a:oracle:enterprise_manager_ops_center:12.4.0:*:*:*:*:*:*:*
cpe:2.3:a:oracle:http_server:12.2.1.3.0:*:*:*:*:*:*:*
cpe:2.3:a:oracle:instantis_enterprisetrack:17.1:*:*:*:*:*:*:*
+ 4 more

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Same weakness CWE-444 – HTTP Request/Response Smuggling

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Same technique Denial Of Service

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CVE-2011-0609 HIGH POC
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References

Advisories & patches
PATCH http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00051.html PATCH http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00061.html PATCH http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00084.html PATCH https://www.oracle.com/technetwork/security-advisory/cpujul2019-5072835.html PATCH https://www.oracle.com/technetwork/security-advisory/cpuoct2019-5072832.html ADVISORY https://httpd.apache.org/security/vulnerabilities_24.html REF http://www.openwall.com/lists/oss-security/2019/04/02/2 REF http://www.securityfocus.com/bid/107665 REF https://access.redhat.com/errata/RHSA-2019:3932 REF https://access.redhat.com/errata/RHSA-2019:3933 REF https://access.redhat.com/errata/RHSA-2019:3935 REF https://lists.apache.org/thread.html/56c2e7cc9deb1c12a843d0dc251ea7fd3e7e80293cde02fcd65286ba%40%3Ccvs.httpd.apache.org%3E REF https://lists.apache.org/thread.html/84a3714f0878781f6ed84473d1a503d2cc382277e100450209231830%40%3Ccvs.httpd.apache.org%3E REF https://lists.apache.org/thread.html/e0b8f6e858b1c8ec2ce8e291a2c543d438915037c7af661ab6d33808%40%3Cdev.httpd.apache.org%3E REF https://lists.apache.org/thread.html/r03ee478b3dda3e381fd6189366fa7af97c980d2f602846eef935277d%40%3Ccvs.httpd.apache.org%3E REF https://lists.apache.org/thread.html/r06f0d87ebb6d59ed8379633f36f72f5b1f79cadfda72ede0830b42cf%40%3Ccvs.httpd.apache.org%3E REF https://lists.apache.org/thread.html/r76142b8c5119df2178be7c2dba88fde552eedeec37ea993dfce68d1d%40%3Ccvs.httpd.apache.org%3E REF https://lists.apache.org/thread.html/r9f93cf6dde308d42a9c807784e8102600d0397f5f834890708bf6920%40%3Ccvs.httpd.apache.org%3E REF https://lists.apache.org/thread.html/rc998b18880df98bafaade071346690c2bc1444adaa1a1ea464b93f0a%40%3Ccvs.httpd.apache.org%3E REF https://lists.apache.org/thread.html/rd18c3c43602e66f9cdcf09f1de233804975b9572b0456cc582390b6f%40%3Ccvs.httpd.apache.org%3E REF https://lists.apache.org/thread.html/rd2fb621142e7fa187cfe12d7137bf66e7234abcbbcd800074c84a538%40%3Ccvs.httpd.apache.org%3E REF https://lists.apache.org/thread.html/re3d27b6250aa8548b8845d314bb8a350b3df326cacbbfdfe4d455234%40%3Ccvs.httpd.apache.org%3E REF https://lists.apache.org/thread.html/re473305a65b4db888e3556e4dae10c2a04ee89dcff2e26ecdbd860a9%40%3Ccvs.httpd.apache.org%3E REF https://lists.apache.org/thread.html/rf6449464fd8b7437704c55f88361b66f12d5b5f90bcce66af4be4ba9%40%3Ccvs.httpd.apache.org%3E REF https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WETXNQWNQLWHV6XNW6YTO5UGDTIWAQGT/ REF https://security.netapp.com/advisory/ntap-20190617-0002/ REF https://support.f5.com/csp/article/K44591505 REF https://support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03950en_us REF https://usn.ubuntu.com/4113-1/ REF https://www.oracle.com/security-alerts/cpuapr2020.html

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