QID 198413

Date Published: 2021-06-28

QID 198413: Ubuntu Security Notification for Apache HTTP Server vulnerabilities (USN-4994-1)

The apache mod_proxy_http module incorrectly handled certain requests.
The apache mod_auth_digest module incorrectly handled certain digest nonces.
The apache mod_session module incorrectly handled certain cookie headers.
The apache mod_session module incorrectly handled certain sessionheader values.
The new mergeslashes configuration option resulted in unexpected behaviour in certain situations.

Note: The preceding description block is extracted directly from the security advisory. Using automation, we have attempted to clean and format it as much as possible without introducing additional issues.

a remote attacker could possibly use this issue to cause apache to crash, resulting in a denial of service.
This issue only affected ubuntu 20.04 lts, ubuntu 20.10, and ubuntu 21.04. (
Cve-2020-13950).
A remote attacker could possibly use this issue to cause apache to crash, resulting in a denial of service.
(cve-2020-35452).
A remote attacker could possibly use this issue to cause apache to crash, resulting in a denial of service.
(cve-2021-26690).
A remote attacker could use this issue to cause apache to crash, resulting in a denial of service, or possibly execute arbitrary code. (
Cve-2021-26691).
(cve-2021-30641).

  • CVSS V3 rated as Critical - 9.8 severity.
  • CVSS V2 rated as High - 7.5 severity.
    • Solution
    Refer to Ubuntu advisory: USN-4994-1 for affected packages and patching details, or update with your package manager.
    Vendor References

    CVEs related to QID 198413

    CVE-2021-26690 | CVE-2020-13950 | CVE-2020-35452 | CVE-2021-30641 | CVE-2021-26691 |
    Software Advisories
    Advisory ID Software Component Link
    USN-4994-1 Ubuntu Linux URL Logo usn.ubuntu.com/4994-1
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