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Curl CVE-2026-3805

HIGH
Use After Free (CWE-416)
2026-03-11 2499f714-1537-4658-8207-48ae4bb9eae9
Information Disclosure Use After Free Memory Corruption Curl Haxx
7.5
CVSS 3.1 · Vendor: 2499f714-1537-4658-8207-48ae4bb9eae9
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Attack ChainAIDerived

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

  1. Access
    Send initial SMB request to curl
  2. Exploit
    Send second SMB request to same host
  3. Execution
    Curl reuses freed memory pointer
  4. Impact
    Denial of service via crash

Vulnerability Assessment

Weakness
CWE
CWE-416
OWASP Top 10:2025
A06:2021 - Vulnerable and Outdated Components
ASVS 5.0
V15 - Secure Coding and Architecture Memory lifecycle management
MITRE ATT&CK

2 techniques across 2 tactics: Execution, Privilege Escalation

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

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Exploitation Conditions

No special conditions — remote unauthenticated exploitation against curl with SMB protocol support enabled connecting to any SMB server.
Impact

CVSS 7.5 (HIGH). 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 Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

Curl's SMB implementation contains a use-after-free vulnerability that causes denial of service when processing consecutive requests to the same host, as the library incorrectly dereferences freed memory on subsequent connections. Public exploit code exists for this vulnerability affecting Curl installations. An attacker can crash Curl-based applications or services by triggering multiple SMB requests, though remote code execution is not possible due to the nature of the memory corruption.

Earlier versions of this analysis (1)
v1 Mar 12, 2026 - 22:06 CVSS 7.5

When doing a second SMB request to the same host again, curl would wrongly use a data pointer pointing into already freed memory. [CVSS 7.5 HIGH]

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.

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

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Technical ContextAI · show details

Classified as CWE-416 (Use After Free). Affects Curl. When doing a second SMB request to the same host again, curl would wrongly use a data pointer pointing into already freed memory.

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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 7.5 HIGH
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SUSE HIGH
Red Hat 6.3 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
None
Integrity
None
Availability
High

Lifecycle Timeline

3
PoC Detected
Mar 12, 2026 - 14:08 vuln.today
Public exploit code
Patch released
Mar 12, 2026 - 14:08 nvd
Patch available
CVE Published
Mar 11, 2026 - 11:16 nvd
HIGH 7.5

DescriptionCVE.org

When doing a second SMB request to the same host again, curl would wrongly use a data pointer pointing into already freed memory.

Executive ViewAI

Why It Matters

CVE-2026-3805 is a memory safety vulnerability in curl that could allow attackers to execute arbitrary code or cause denial of service when making consecutive SMB requests. Organizations using curl for file transfer operations face immediate risk of system compromise, particularly in environments automating backup, data transfer, or network administration tasks.

Business Impact: High
Compensating Controls

Apply vendor patch. If immediate patching is not feasible: (1) disable SMB protocol support in curl if not required for operations; (2) restrict curl execution to trusted internal networks only using firewall rules; (3) implement application-level input validation for file transfer requests; (4) monitor for exploitation attempts targeting curl processes.

Threat Intelligence Overview

EPSS Score
0.0%
Top 88% exploitable
Exploit
POC
Public exploit code exists
Data Quality
5 sources
Confidence: Medium
NVD CVE.org EPSS 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 HIGH
CISA KEV No
Public POC Yes
EPSS 0.0%
Patch available Yes
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· derived
Out-of-Cycle
Exploitation· derived
Poc
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact
High

Priority Score

58
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +38
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Use After Free HIGH

Use-after-free vulnerabilities occur when a program continues to access memory through a pointer after that memory has been deallocated.

Memory Corruption HIGH

Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.

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:*:*:*:*:*:*:*:*

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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
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7.5 Mar 08

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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
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1. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack co
CVE-2023-23914 CRITICAL POC
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A cleartext transmission of sensitive information vulnerability exists in curl <v7.88.0 that could cause HSTS functional
CVE-2023-27534 HIGH POC
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Same weakness CWE-416 – Use After Free

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CVE-2019-0708 CRITICAL POC
9.8
CVE-2015-5119 CRITICAL POC
9.8
CVE-2014-0322 HIGH POC
8.8
CVE-2012-4792 HIGH POC
8.8
CVE-2009-4324 HIGH POC
7.8
CVE-2015-0313 CRITICAL POC
9.8
CVE-2015-5122 CRITICAL POC
9.8
CVE-2013-2551 HIGH POC
8.8

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: High
Product Status
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
Container suse/sl-micro/6.0/base-os-container:2.1.3-7.107 Container suse/sl-micro/6.0/toolbox:13.2-9.77 Image SL-Micro Affected

References

Advisories & patches
PATCH https://curl.se/docs/CVE-2026-3805.html ADVISORY https://curl.se/docs/CVE-2026-3805.json ADVISORY https://ubuntu.com/security/notices/USN-8084-1 ADVISORY https://vuldb.com/?id.350378 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-2026:20668/ 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/2026/03/11/4

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