Fedora 27 update for libxml2

Published: 2018-01-24 | Updated: 2025-04-24

Risk	High
Patch available	YES
Number of vulnerabilities	7
CVE-ID	CVE-2016-5131 CVE-2016-4658 CVE-2017-8872 CVE-2017-9047 CVE-2017-9048 CVE-2017-9049 CVE-2017-9050
CWE-ID	CWE-416 CWE-126 CWE-119 CWE-121
Exploitation vector	Network
Public exploit	Public exploit code for vulnerability #3 is available. Public exploit code for vulnerability #4 is available. Public exploit code for vulnerability #5 is available. Public exploit code for vulnerability #6 is available. Public exploit code for vulnerability #7 is available.
Vulnerable software	Fedora Operating systems & Components / Operating system libxml2 Operating systems & Components / Operating system package or component
Vendor	Fedoraproject

Security Bulletin

This security bulletin contains information about 7 vulnerabilities.

1) Use-after-free

EUVDB-ID: #VU33135

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-2016-5131

CWE-ID: CWE-416 - Use After Free

Exploit availability: No

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a use-after-free error when processing vectors related to the XPointer range-to function. A remote attackers can cause a denial of service or execute arbitrary code on the target system.

Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable system.

Mitigation

Install updates from vendor's repository.

Vulnerable software versions

Fedora: 27

libxml2: before 2.9.7-1.fc27

CPE2.3

External links

https://bodhi.fedoraproject.org/updates/FEDORA-2018-db610fff5b

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.

2) Use-after-free

EUVDB-ID: #VU57346

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-2016-4658

CWE-ID: CWE-416 - Use After Free

Exploit availability: No

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a use-after-free error, caused by using namespace nodes in XPointer ranges within the xpointer.c in libxml2. A remote attackers can pass specially crated XML document to he application, trigger a use-after-free error and execute arbitrary code on the system.

Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable system.

Mitigation

Install updates from vendor's repository.

Vulnerable software versions

Fedora: 27

libxml2: before 2.9.7-1.fc27

CPE2.3

External links

https://bodhi.fedoraproject.org/updates/FEDORA-2018-db610fff5b

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) 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

Description

The 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.

Mitigation

Install updates from vendor's repository.

Vulnerable software versions

Fedora: 27

libxml2: before 2.9.7-1.fc27

CPE2.3

External links

https://bodhi.fedoraproject.org/updates/FEDORA-2018-db610fff5b

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.

4) Memory corruption

EUVDB-ID: #VU9687

Risk: Low

CVSSv4.0: 5.5 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/U:Clear]

CVE-ID: CVE-2017-9047

CWE-ID: CWE-119 - Memory corruption

Exploit availability: No

Description

The vulnerability allows a remote attacker to cause DoS condition on the target system.

The weakness exists in the xmlSnprintfElementContent function of XMLSoft libxml2 due to improper memory handling by the valid.c source code. A remote attacker can send a specially crafted XML file, trigger memory corruption and cause the service to crash.

Successful exploitation of the vulnerability results in denial of service.

Mitigation

Install updates from vendor's repository.

Vulnerable software versions

Fedora: 27

libxml2: before 2.9.7-1.fc27

CPE2.3

External links

https://bodhi.fedoraproject.org/updates/FEDORA-2018-db610fff5b

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.

5) Stack-based buffer overflow

EUVDB-ID: #VU9691

Risk: Low

CVSSv4.0: 5.5 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/U:Clear]

CVE-ID: CVE-2017-9048

CWE-ID: CWE-121 - Stack-based buffer overflow

Exploit availability: No

Description

The vulnerability allows a remote attacker to cause DoS condition on the target system.

The weakness exists in the xmlSnprintfElementContent function of XMLSoft libxml2 due to improper bounds checking in the valid.c code. A remote attacker can send a specially crafted request, trigger stack-based buffer overflow condition and cause the service to crash.

Successful exploitation of the vulnerability results in denial of service.

Mitigation

Install updates from vendor's repository.

Vulnerable software versions

Fedora: 27

libxml2: before 2.9.7-1.fc27

CPE2.3

External links

https://bodhi.fedoraproject.org/updates/FEDORA-2018-db610fff5b

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.

6) Heap-based buffer over-read

EUVDB-ID: #VU9688

Risk: Low

CVSSv4.0: 5.5 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/U:Clear]

CVE-ID: CVE-2017-9049

CWE-ID: CWE-126 - Buffer over-read

Exploit availability: No

Description

The vulnerability allows a remote attacker to cause DoS condition on the target system.

The weakness exists in the xmlDictComputeFastKey function of XMLSoft libxml2 due to improper bounds checking in the dict.c code. A remote attacker can send a specially crafted request, trigger heap-based buffer over-read condition and cause the service to crash.

Successful exploitation of the vulnerability results in denial of service.

Mitigation

Install updates from vendor's repository.

Vulnerable software versions

Fedora: 27

libxml2: before 2.9.7-1.fc27

CPE2.3

External links

https://bodhi.fedoraproject.org/updates/FEDORA-2018-db610fff5b

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.

7) Heap-based buffer over-read

EUVDB-ID: #VU9689

Risk: Low

CVSSv4.0: 5.5 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/U:Clear]

CVE-ID: CVE-2017-9050

CWE-ID: CWE-126 - Buffer over-read

Exploit availability: No

Description

The vulnerability allows a remote attacker to cause DoS condition on the target system.

The weakness exists in the xmlDictAddString function of XMLSoft libxml2 due to improper bounds checking in the dict.c code. A remote attacker can send a specially crafted request, trigger heap-based buffer over-read condition and cause the service to crash.

Successful exploitation of the vulnerability results in denial of service.

Mitigation

Install updates from vendor's repository.

Vulnerable software versions

Fedora: 27

libxml2: before 2.9.7-1.fc27

CPE2.3

External links

https://bodhi.fedoraproject.org/updates/FEDORA-2018-db610fff5b

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.