Ubuntu update for libxml2
| Risk | High |
| Patch available | YES |
| Number of vulnerabilities | 8 |
| CVE-ID | CVE-2017-8872 CVE-2019-20388 CVE-2020-24977 CVE-2021-3516 CVE-2021-3517 CVE-2021-3518 CVE-2021-3537 CVE-2021-3541 |
| CWE-ID | CWE-126 CWE-401 CWE-125 CWE-416 CWE-787 CWE-476 CWE-20 |
| Exploitation vector | Network |
| Public exploit | Public exploit code for vulnerability #1 is available. |
| Vulnerable software |
Ubuntu Operating systems & Components / Operating system libxml2-utils (Ubuntu package) Operating systems & Components / Operating system package or component libxml2 (Ubuntu package) Operating systems & Components / Operating system package or component |
| Vendor | Canonical Ltd. |
Security Bulletin
This security bulletin contains information about 8 vulnerabilities.
1) Buffer over-read
EUVDB-ID: #VU9690
Risk: Low
CVSSv4.0: 2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/U:Clear]
CVE-ID: CVE-2017-8872
CWE-ID:
CWE-126 - Buffer over-read
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to obtain potentially sensitive information or cause DoS condition on the target system.
The weakness exists in the htmlParseTryOrFinish function of XMLSoft libxml2 due to buffer over-read condition in the HTMLparser.c source code. A remote attacker can send a specially crafted XML file, trick the victim into opening it and read arbitrary data or cause the service to crash.
Successful exploitation of the vulnerability results in denial of service.
Update the affected package libxml2 to the latest version.
Vulnerable software versionsUbuntu: 14.04 - 21.04
libxml2-utils (Ubuntu package): before 2.9.4+dfsg1-6.1ubuntu1.4
libxml2 (Ubuntu package): before 2.9.4+dfsg1-6.1ubuntu1.4
CPE2.3- cpe:2.3:o:canonical:ubuntu:14.04:*:*:*:*:*:*:*
- cpe:2.3:o:canonical:ubuntu:16.04:*:*:*:*:*:*:*
- cpe:2.3:o:canonical:ubuntu:18.04:*:*:*:*:*:*:*
- cpe:2.3:o:canonical:ubuntu:20.04:*:*:*:*:*:*:*
- cpe:2.3:o:canonical:ubuntu:20.10:*:*:*:*:*:*:*
- cpe:2.3:o:canonical:ubuntu:21.04:*:*:*:*:*:*:*
- cpe:2.3:o:canonical:libxml2-utils_ubuntu_package:*:*:*:*:*:ubuntu:*:*
- cpe:2.3:o:canonical:libxml2_ubuntu_package:*:*:*:*:*:ubuntu:*:*
https://ubuntu.com/security/notices/USN-4991-1
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.
2) Memory leak
EUVDB-ID: #VU24487
Risk: Medium
CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]
CVE-ID: CVE-2019-20388
CWE-ID:
CWE-401 - Missing release of memory after effective lifetime
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to perform DoS attack on the target system.
The vulnerability exists due memory leak in xmlSchemaPreRun in xmlschemas.c. A remote attacker can trigger a xmlSchemaValidateStream memory leak and perform denial of service attack.
MitigationUpdate the affected package libxml2 to the latest version.
Vulnerable software versionsUbuntu: 14.04 - 21.04
libxml2-utils (Ubuntu package): before 2.9.4+dfsg1-6.1ubuntu1.4
libxml2 (Ubuntu package): before 2.9.4+dfsg1-6.1ubuntu1.4
CPE2.3- cpe:2.3:o:canonical:libxml2-utils_ubuntu_package:*:*:*:*:*:ubuntu:*:*
- cpe:2.3:o:canonical:libxml2_ubuntu_package:*:*:*:*:*:ubuntu:*:*
https://ubuntu.com/security/notices/USN-4991-1
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
3) Out-of-bounds read
EUVDB-ID: #VU46737
Risk: Medium
CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]
CVE-ID: CVE-2020-24977
CWE-ID:
CWE-125 - Out-of-bounds read
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to gain access to potentially sensitive information.
The vulnerability exists due to a boundary condition within the xmlEncodeEntitiesInternal() function in libxml2/entities.c in libxml2. A remote attacker can pas specially crafted XML data to the affected application, trigger out-of-bounds read error and read contents of memory on the system.
MitigationUpdate the affected package libxml2 to the latest version.
Vulnerable software versionsUbuntu: 14.04 - 21.04
libxml2-utils (Ubuntu package): before 2.9.4+dfsg1-6.1ubuntu1.4
libxml2 (Ubuntu package): before 2.9.4+dfsg1-6.1ubuntu1.4
CPE2.3- cpe:2.3:o:canonical:libxml2-utils_ubuntu_package:*:*:*:*:*:ubuntu:*:*
- cpe:2.3:o:canonical:libxml2_ubuntu_package:*:*:*:*:*:ubuntu:*:*
https://ubuntu.com/security/notices/USN-4991-1
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
4) Use-after-free
EUVDB-ID: #VU54222
Risk: High
CVSSv4.0: 6.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]
CVE-ID: CVE-2021-3516
CWE-ID:
CWE-416 - Use After Free
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to compromise vulnerable system.
The vulnerability exists due to a use-after-free error in xmllint. A remote attacker can use a specially crafted file to execute arbitrary code on the target system.
Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable system.
MitigationUpdate the affected package libxml2 to the latest version.
Vulnerable software versionsUbuntu: 14.04 - 21.04
libxml2-utils (Ubuntu package): before 2.9.4+dfsg1-6.1ubuntu1.4
libxml2 (Ubuntu package): before 2.9.4+dfsg1-6.1ubuntu1.4
CPE2.3- cpe:2.3:o:canonical:libxml2-utils_ubuntu_package:*:*:*:*:*:ubuntu:*:*
- cpe:2.3:o:canonical:libxml2_ubuntu_package:*:*:*:*:*:ubuntu:*:*
https://ubuntu.com/security/notices/USN-4991-1
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
5) Out-of-bounds write
EUVDB-ID: #VU54224
Risk: High
CVSSv4.0: 8.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]
CVE-ID: CVE-2021-3517
CWE-ID:
CWE-787 - Out-of-bounds write
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to compromise vulnerable system.
The vulnerability exists due to a boundary error when processing untrusted input in the xml entity encoding functionality. A remote attacker can create a specially crafted file, trick the victim into opening it using the affected software, trigger out-of-bounds write and execute arbitrary code on the target system.
MitigationUpdate the affected package libxml2 to the latest version.
Vulnerable software versionsUbuntu: 14.04 - 21.04
libxml2-utils (Ubuntu package): before 2.9.4+dfsg1-6.1ubuntu1.4
libxml2 (Ubuntu package): before 2.9.4+dfsg1-6.1ubuntu1.4
CPE2.3- cpe:2.3:o:canonical:libxml2-utils_ubuntu_package:*:*:*:*:*:ubuntu:*:*
- cpe:2.3:o:canonical:libxml2_ubuntu_package:*:*:*:*:*:ubuntu:*:*
https://ubuntu.com/security/notices/USN-4991-1
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
6) Use-after-free
EUVDB-ID: #VU54225
Risk: High
CVSSv4.0: 6.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]
CVE-ID: CVE-2021-3518
CWE-ID:
CWE-416 - Use After Free
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to compromise vulnerable system.
The vulnerability exists due to a use-after-free error in libxml2. A remote attacker can use a specially crafted file and execute arbitrary code on the target system.
Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable system.
MitigationUpdate the affected package libxml2 to the latest version.
Vulnerable software versionsUbuntu: 14.04 - 21.04
libxml2-utils (Ubuntu package): before 2.9.4+dfsg1-6.1ubuntu1.4
libxml2 (Ubuntu package): before 2.9.4+dfsg1-6.1ubuntu1.4
CPE2.3- cpe:2.3:o:canonical:libxml2-utils_ubuntu_package:*:*:*:*:*:ubuntu:*:*
- cpe:2.3:o:canonical:libxml2_ubuntu_package:*:*:*:*:*:ubuntu:*:*
https://ubuntu.com/security/notices/USN-4991-1
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
7) NULL pointer dereference
EUVDB-ID: #VU54223
Risk: Medium
CVSSv4.0: 4.6 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]
CVE-ID: CVE-2021-3537
CWE-ID:
CWE-476 - NULL Pointer Dereference
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to a NULL pointer dereference error. A remote attacker can pass specially crafted data to the application and perform a denial of service (DoS) attack.
MitigationUpdate the affected package libxml2 to the latest version.
Vulnerable software versionsUbuntu: 14.04 - 21.04
libxml2-utils (Ubuntu package): before 2.9.4+dfsg1-6.1ubuntu1.4
libxml2 (Ubuntu package): before 2.9.4+dfsg1-6.1ubuntu1.4
CPE2.3- cpe:2.3:o:canonical:libxml2-utils_ubuntu_package:*:*:*:*:*:ubuntu:*:*
- cpe:2.3:o:canonical:libxml2_ubuntu_package:*:*:*:*:*:ubuntu:*:*
https://ubuntu.com/security/notices/USN-4991-1
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
8) Input validation error
EUVDB-ID: #VU53289
Risk: Medium
CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]
CVE-ID: CVE-2021-3541
CWE-ID:
CWE-20 - Improper input validation
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to insufficient validation of user-supplied input. A remote attacker can pass specially crafted input to the application and perform a denial of service (DoS) attack.
MitigationUpdate the affected package libxml2 to the latest version.
Vulnerable software versionsUbuntu: 14.04 - 21.04
libxml2-utils (Ubuntu package): before 2.9.4+dfsg1-6.1ubuntu1.4
libxml2 (Ubuntu package): before 2.9.4+dfsg1-6.1ubuntu1.4
CPE2.3- cpe:2.3:o:canonical:libxml2-utils_ubuntu_package:*:*:*:*:*:ubuntu:*:*
- cpe:2.3:o:canonical:libxml2_ubuntu_package:*:*:*:*:*:ubuntu:*:*
https://ubuntu.com/security/notices/USN-4991-1
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
