Ubuntu update for apache2
| Risk | Medium |
| Patch available | YES |
| Number of vulnerabilities | 4 |
| CVE-ID | CVE-2020-35452 CVE-2021-26690 CVE-2021-26691 CVE-2021-30641 |
| CWE-ID | CWE-121 CWE-476 CWE-20 |
| Exploitation vector | Network |
| Public exploit | N/A |
| Vulnerable software |
Ubuntu Operating systems & Components / Operating system apache2-bin (Ubuntu package) Operating systems & Components / Operating system package or component apache2 (Ubuntu package) Operating systems & Components / Operating system package or component |
| Vendor | Canonical Ltd. |
Security Bulletin
This security bulletin contains information about 4 vulnerabilities.
1) Stack-based buffer overflow
EUVDB-ID: #VU53775
Risk: Medium
CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]
CVE-ID: CVE-2020-35452
CWE-ID:
CWE-121 - Stack-based buffer overflow
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to a boundary error when processing Digest nounces in mod_auth_digest. A remote unauthenticated attacker can send a specially crafted HTTP request, trigger stack overflow by one nul byte and crash the server.
Update the affected package apache2 to the latest version.
Vulnerable software versionsUbuntu: 14.04 - 16.04
apache2-bin (Ubuntu package): before 2.4.182u buntu3.17+esm1
apache2 (Ubuntu package): before 2.4.182u buntu3.17+esm1
CPE2.3- cpe:2.3:o:canonical:ubuntu:14.04:*:*:*:*:*:*:
- cpe:2.3:o:canonical:ubuntu:16.04:*:*:*:*:*:*:
- cpe:2.3:o:canonical:apache2-bin_ubuntu_package:*:*:*:*:*:ubuntu:*:
- cpe:2.3:o:canonical:apache2_ubuntu_package:*:*:*:*:*:ubuntu:*:
http://ubuntu.com/security/notices/USN-4994-2
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) NULL pointer dereference
EUVDB-ID: #VU53777
Risk: Medium
CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]
CVE-ID: CVE-2021-26690
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 in mod_session. A remote attacker can pass specially crafted data to the application and perform a denial of service (DoS) attack.
MitigationUpdate the affected package apache2 to the latest version.
Vulnerable software versionsUbuntu: 14.04 - 16.04
apache2-bin (Ubuntu package): before 2.4.182u buntu3.17+esm1
apache2 (Ubuntu package): before 2.4.182u buntu3.17+esm1
CPE2.3- cpe:2.3:o:canonical:apache2-bin_ubuntu_package:*:*:*:*:*:ubuntu:*:
- cpe:2.3:o:canonical:apache2_ubuntu_package:*:*:*:*:*:ubuntu:*:
http://ubuntu.com/security/notices/USN-4994-2
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) NULL pointer dereference
EUVDB-ID: #VU53776
Risk: Low
CVSSv3.1: 5.2 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]
CVE-ID: CVE-2021-26691
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 in mod_session. A a malicious backend server or SessionHeader can trigger a denial of service (DoS) condition.
MitigationUpdate the affected package apache2 to the latest version.
Vulnerable software versionsUbuntu: 14.04 - 16.04
apache2-bin (Ubuntu package): before 2.4.182u buntu3.17+esm1
apache2 (Ubuntu package): before 2.4.182u buntu3.17+esm1
CPE2.3- cpe:2.3:o:canonical:apache2-bin_ubuntu_package:*:*:*:*:*:ubuntu:*:
- cpe:2.3:o:canonical:apache2_ubuntu_package:*:*:*:*:*:ubuntu:*:
http://ubuntu.com/security/notices/USN-4994-2
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) Input validation error
EUVDB-ID: #VU53774
Risk: Medium
CVSSv3.1: 6.4 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C]
CVE-ID: CVE-2021-30641
CWE-ID:
CWE-20 - Improper input validation
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to bypass implemented security restrictions.
The vulnerability exists due to incorrect parsing of Apache configuration files. An unexpected
Update the affected package apache2 to the latest version.
Vulnerable software versionsUbuntu: 14.04 - 16.04
apache2-bin (Ubuntu package): before 2.4.182u buntu3.17+esm1
apache2 (Ubuntu package): before 2.4.182u buntu3.17+esm1
CPE2.3- cpe:2.3:o:canonical:apache2-bin_ubuntu_package:*:*:*:*:*:ubuntu:*:
- cpe:2.3:o:canonical:apache2_ubuntu_package:*:*:*:*:*:ubuntu:*:
http://ubuntu.com/security/notices/USN-4994-2
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.
