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Curl CVE-2026-3784

MEDIUM
Authentication Bypass by Primary Weakness (CWE-305)
2026-03-11 2499f714-1537-4658-8207-48ae4bb9eae9
Information Disclosure Curl Haxx
6.5
CVSS 3.1 · Vendor: 2499f714-1537-4658-8207-48ae4bb9eae9
View

Vulnerability Assessment

Weakness
CWE
CWE-305
OWASP Top 10:2025
A07:2025 - Authentication Failures
ASVS 5.0
V6 - Authentication Primary weakness mitigation
Impact

CVSS 6.5 (MEDIUM). Attack vector: Network. Complexity: Low. Privileges required: None. User interaction: None. Public exploit/POC available.
Exploit ScenarioDerived

An attacker could exploit this vulnerability to compromise the affected system.
This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

curl's HTTP proxy connection reuse mechanism fails to validate credential changes, allowing an attacker to intercept or manipulate traffic by leveraging an existing proxy connection established with different authentication. This affects users whose applications reuse proxy connections across requests with varying credentials, enabling credential confusion attacks. Public exploit code exists for this vulnerability, though a patch is available.

Earlier versions of this analysis (1)
v1 Mar 12, 2026 - 22:06 CVSS 6.5

curl would wrongly reuse an existing HTTP proxy connection doing CONNECT to a server, even if the new request uses different credentials for the HTTP proxy. The proper behavior is to create or use a separate connection. [CVSS 6.5 MEDIUM]

RemediationAI

A vendor patch is available — apply it immediately. Restrict network access to the affected service where possible.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

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Technical ContextAI · show details

Affects Curl. curl would wrongly reuse an existing HTTP proxy connection doing CONNECT to a server, even if the new request uses different credentials for the HTTP proxy. The proper behavior is to create or use a separate connection.

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

Vendor (2499f714-1537-4658-8207-48ae4bb9eae9) PRIMARY 6.5 MEDIUM
AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
SUSE MEDIUM
Red Hat 6.5 MEDIUM

Primary rating from Vendor (2499f714-1537-4658-8207-48ae4bb9eae9).

CVSS VectorVendor: 2499f714-1537-4658-8207-48ae4bb9eae9

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

Lifecycle Timeline

3
PoC Detected
Mar 12, 2026 - 14:09 vuln.today
Public exploit code
Patch released
Mar 12, 2026 - 14:09 nvd
Patch available
CVE Published
Mar 11, 2026 - 11:16 nvd
MEDIUM 6.5

DescriptionCVE.org

curl would wrongly reuse an existing HTTP proxy connection doing CONNECT to a server, even if the new request uses different credentials for the HTTP proxy. The proper behavior is to create or use a separate connection.

Executive ViewAI

Why It Matters

CVE-2026-3784 presents notable security risk rated CVSS 6.5. Exploitation could compromise the security of affected deployments. Proof-of-concept code is publicly available. A patch is available and should be applied during regular vulnerability management.

Business Impact: Moderate
Compensating Controls

Apply vendor patch. If patching is delayed: restrict network access and enable monitoring.

Threat Intelligence Overview

Threat Score
4.8/10
Composite threat intelligence
EPSS Score
0.0%
Top 92% exploitable
Threat Intel
1
1 source
Exploit
POC
Public exploit code exists
Data Quality
6 sources
Confidence: High
NVD CVE.org EPSS CISA Vendor VulDB

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 Yes
EPSS 0.0%
Patch available Yes
Active threat Yes
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

Exploitation· derived
Poc
System Exposure· derived
Open
Automatable· derived
Yes

Priority Score

62
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +32
PoC: +20
Weaponized: 0
Threat intel: +10
Gov advisory: 0

Attack Technique

Information Disclosure MEDIUM

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

Affected Products (CPE)CVE.org

cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*

Related Vulnerabilities in curl Connection Reuse and Token Leakage

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CVE-2026-1965 MEDIUM
6.5
CVE-2026-3805 HIGH POC
7.5
CVE-2026-3783 MEDIUM POC
5.3

More in Curl

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CVE-2021-22901 HIGH POC
8.1 Jun 11

curl 7.75.0 through 7.76.1 suffers from a use-after-free vulnerability resulting in already freed memory being used when
CVE-2013-0249 HIGH POC
7.5 Mar 08

Stack-based buffer overflow in the Curl_sasl_create_digest_md5_message function in lib/curl_sasl.c in curl and libcurl 7
CVE-2015-3145 HIGH
7.5 Apr 24

The sanitize_cookie_path function in cURL and libcurl 7.31.0 through 7.41.0 does not properly calculate an index, which

CVE-2022-32206 MEDIUM POC
6.5 Jul 07

curl < 7.84.0 supports "chained" HTTP compression algorithms, meaning that a serverresponse can be compressed multiple t
CVE-2022-32207 CRITICAL POC
9.8 Jul 07

When curl < 7.84.0 saves cookies, alt-svc and hsts data to local files, it makes the operation atomic by finalizing the

CVE-2022-43551 HIGH POC
7.5 Dec 23

A vulnerability exists in curl <7.87.0 HSTS check that could be bypassed to trick it to keep using HTTP. Rated high seve
CVE-2022-32221 CRITICAL POC
9.8 Dec 05

When doing HTTP(S) transfers, libcurl might erroneously use the read callback (`CURLOPT_READFUNCTION`) to ask for data t
CVE-2018-0500 CRITICAL POC
9.8 Jul 11

Curl_smtp_escape_eob in lib/smtp.c in curl 7.54.1 to and including curl 7.60.0 has a heap-based buffer overflow that mig
CVE-2022-32205 MEDIUM POC
4.3 Jul 07

A malicious server can serve excessive amounts of `Set-Cookie:` headers in a HTTP response to curl and curl < 7.84.0 sto
CVE-2025-9086 HIGH POC
7.5 Sep 12

1. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack co
CVE-2023-23914 CRITICAL POC
9.1 Feb 23

A cleartext transmission of sensitive information vulnerability exists in curl <v7.88.0 that could cause HSTS functional
CVE-2023-27534 HIGH POC
8.8 Mar 30

A path traversal vulnerability exists in curl <8.0.0 SFTP implementation causes the tilde (~) character to be wrongly re

Same weakness CWE-305 – Authentication Bypass by Primary Weakness

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CVE-2025-31161 CRITICAL POC
9.8
CVE-2026-81578 HIGH POC
8.8
CVE-2024-50478 CRITICAL
9.8
CVE-2023-34124 CRITICAL POC
9.8
CVE-2026-25555 CRITICAL POC
9.3
CVE-2023-1307 CRITICAL POC
9.8
CVE-2023-0777 CRITICAL POC
9.8
CVE-2022-2651 CRITICAL POC
9.8

Same technique Information Disclosure

View all
CVE-2019-2725 CRITICAL POC
9.8
CVE-2021-34523 CRITICAL POC
9.0
CVE-2013-2251 CRITICAL POC
9.8
CVE-2017-5638 CRITICAL POC
9.8
CVE-2025-24813 CRITICAL POC
9.8
CVE-2025-68613 HIGH POC
8.8
CVE-2015-1701 HIGH POC
7.8
CVE-2017-0147 HIGH POC
7.5

Vendor StatusVendor

SUSE

Severity: Medium
Product Status
Container suse/ltss/sle12.5/sles12sp5:8.5.210 Affected
Container suse/manager/4.3/proxy-httpd:4.3.16.2.9.73.25 Container suse/manager/4.3/proxy-salt-broker:4.3.16.2.9.63.26 Container suse/sle-micro/base-5.5:2.0.4-5.8.252 Image SLES15-SP5-Micro-5-5 Image SLES15-SP5-Micro-5-5-Azure Image SLES15-SP5-SAP-Azure-LI-BYOS Image SLES15-SP5-SAP-Azure-LI-BYOS-Production Image SLES15-SP5-SAP-Azure-VLI-BYOS Image SLES15-SP5-SAP-Azure-VLI-BYOS-Production Affected
Container suse/manager/5.0/x86_64/proxy-httpd:latest Container suse/manager/5.0/x86_64/proxy-salt-broker:latest Container suse/manager/5.0/x86_64/server:latest Image SLES15-SP6-SAP-Azure-LI-BYOS Image SLES15-SP6-SAP-Azure-LI-BYOS-Production Image SLES15-SP6-SAP-Azure-VLI-BYOS Image SLES15-SP6-SAP-Azure-VLI-BYOS-Production Affected
Container suse/manager/5.0/x86_64/server-hub-xmlrpc-api:latest Container suse/manager/5.0/x86_64/server-migration-14-16:latest Affected
Container suse/sl-micro/6.0/baremetal-os-container:2.1.3-6.140 Affected

Threat IntelligenceMISP

CISA Advisories
ICSA-26-188-05
Sources: CISA (public domain)

References

Advisories & patches
PATCH https://curl.se/docs/CVE-2026-3784.html ADVISORY https://curl.se/docs/CVE-2026-3784.json ADVISORY https://ubuntu.com/security/notices/USN-8084-1 ADVISORY https://vuldb.com/?id.350376 ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:0879/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:0885/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:0903/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:0911/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:0921/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:20668/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:20722/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:20760/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:20918/ REF http://www.openwall.com/lists/oss-security/2026/03/11/3 REF https://cert-portal.siemens.com/productcert/html/ssa-253495.html

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