libcURL up to 7.63.x smtp_endofresp out-of-bounds

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
6.3	$0-$5k	0.00

Summaryinfo

A vulnerability classified as critical has been found in libcURL up to 7.63.x. Impacted is the function smtp_endofresp. The manipulation leads to out-of-bounds. This vulnerability is traded as CVE-2019-3823. It is possible to initiate the attack remotely. There is no exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, has been found in libcURL up to 7.63.x (Network Utility Software). This issue affects the function smtp_endofresp. The manipulation with an unknown input leads to a out-of-bounds vulnerability. Using CWE to declare the problem leads to CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

libcurl versions from 7.34.0 to before 7.64.0 are vulnerable to a heap out-of-bounds read in the code handling the end-of-response for SMTP. If the buffer passed to `smtp_endofresp()` isn't NUL terminated and contains no character ending the parsed number, and `len` is set to 5, then the `strtol()` call reads beyond the allocated buffer. The read contents will not be returned to the caller.

The bug was discovered 02/06/2019. The weakness was shared 02/06/2019 with Tencent as confirmed bug report (Bugzilla). It is possible to read the advisory at bugzilla.redhat.com. The identification of this vulnerability is CVE-2019-3823 since 01/03/2019. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 236591 (Alibaba Cloud Linux 3 : 0078: curl (ALINUX3-SA-2021:0078)), which helps to determine the existence of the flaw in a target environment. The commercial vulnerability scanner Qualys is able to test this issue with plugin 197366 (Ubuntu Security Notification for Curl Vulnerabilities (USN-3882-1)).

Upgrading to version 7.34.0 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (236591) and SecurityFocus (BID 106947†). The entries VDB-130579, VDB-130618, VDB-133589 and VDB-133491 are related to this item. Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

• Network Utility Software

Name

• libcURL

Version

• 7.0
• 7.1
• 7.2
• 7.3
• 7.4
• 7.5
• 7.6
• 7.7
• 7.8
• 7.9
• 7.10
• 7.11
• 7.12
• 7.13
• 7.14
• 7.15
• 7.16
• 7.17
• 7.18
• 7.19
• 7.20
• 7.21
• 7.22
• 7.23
• 7.24
• 7.25
• 7.26
• 7.27
• 7.28
• 7.29
• 7.30
• 7.31
• 7.32
• 7.33
• 7.34
• 7.35
• 7.36
• 7.37
• 7.38
• 7.39
• 7.40
• 7.41
• 7.42
• 7.43
• 7.44
• 7.45
• 7.46
• 7.47
• 7.48
• 7.49
• 7.50
• 7.51
• 7.52
• 7.53
• 7.54
• 7.55
• 7.56
• 7.57
• 7.58
• 7.59
• 7.60
• 7.61
• 7.62
• 7.63

License

• open-source

CPE 2.3info

• 🔍
• 🔍
• 🔍

CPE 2.2info

• 🔍
• 🔍
• 🔍

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.3

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔍

CNA Base Score: 4.3
CNA Vector (Red Hat, Inc.): 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Out-of-bounds
CWE: CWE-125 / CWE-119
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 236591
Nessus Name: Alibaba Cloud Linux 3 : 0078: curl (ALINUX3-SA-2021:0078)

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: libcURL 7.34.0

Timelineinfo

01/03/2019 🔍
02/06/2019 +34 days 🔍
02/06/2019 +0 days 🔍
02/06/2019 +0 days 🔍
02/07/2019 +1 days 🔍
05/20/2025 +2294 days 🔍

Sourcesinfo

Advisory: RHSA-2019:3701
Organization: Tencent
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2019-3823 (🔍)
GCVE (CVE): GCVE-0-2019-3823
GCVE (VulDB): GCVE-100-130619
SecurityFocus: 106947 - cURL/libcURL CVE-2018-16890 Heap Buffer Overflow Vulnerability

See also: 🔍

Entryinfo

Created: 02/07/2019 09:31
Updated: 05/20/2025 19:36
Changes: 02/07/2019 09:31 (62), 05/08/2020 21:20 (5), 07/06/2023 15:39 (4), 07/06/2023 15:44 (12), 05/20/2025 19:36 (17)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Discussion

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