SB2026111370 - Ubuntu update for apache2
Published: November 13, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 5 vulnerabilities.
1) NULL pointer dereference (CVE-ID: CVE-2026-106023)
CWE-ID: CWE-476 - NULL Pointer Dereference
CVSSv4: 6.9 [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]
The vulnerability allows a remote attacker to cause a denial of service by crashing a child process.
The vulnerability exists due to a null pointer dereference in mod_md when processing HTTP requests. A remote attacker can send a crafted HTTP request to trigger the dereference and crash a child process.
2) Stack-based buffer overflow (CVE-ID: CVE-2026-109163)
CWE-ID: CWE-121 - Stack-based buffer overflow
CVSSv4: 6.9 [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]
The vulnerability allows a remote attacker to corrupt stack memory and potentially cause a denial of service.
The vulnerability exists due to a stack-based buffer overflow in mod_vhost_alias when handling request data. A remote attacker can supply crafted input to overwrite one byte of stack memory and potentially cause a denial of service.
3) Race condition (CVE-ID: CVE-2026-119618)
CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
CVSSv4: 9.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to execute arbitrary code.
The vulnerability exists due to improper synchronization of a shared resource in mod_http2's assign_headers() function when processing requests concurrently. A remote attacker can trigger concurrent access to the shared resource to corrupt heap memory and potentially execute arbitrary code.
4) Interpretation Conflict (CVE-ID: CVE-2026-42356)
CWE-ID: CWE-436 - Interpretation Conflict
CVSSv4: 9.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to execute arbitrary code.
The vulnerability exists due to incorrect handler deployment in Apache HTTP Server when processing internal redirects from CGI programs to non-CGI files in CGI-enabled directories. A remote attacker can trigger an internal redirect from a CGI program to execute arbitrary code.
The target file must not have an extension understood by mod_mime.
5) Incorrect calculation (CVE-ID: CVE-2026-42528)
CWE-ID: CWE-682 - Incorrect Calculation
CVSSv4: 5.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to an incorrect memory calculation in mod_dav when creating WebDAV locks. A remote user can create WebDAV locks to cause a denial of service.
Remediation
Install update from vendor's website.