SB20260528275 - Debian update for starlette
Published: May 28, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 4 vulnerabilities.
1) Input validation error (CVE-ID: CVE-2026-48710)
CWE-ID: CWE-20 - Improper input validation
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to bypass path-based security checks.
The vulnerability exists due to improper input validation in request.url reconstruction when processing a malformed Host header. A remote attacker can send a specially crafted Host header to bypass path-based security checks.
The issue occurs because routing uses the raw HTTP path while security-sensitive code may rely on request.url.path reconstructed from the Host header.
2) Path traversal (CVE-ID: CVE-2023-29159)
CWE-ID: CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
The vulnerability allows a remote attacker to perform directory traversal attacks.
The vulnerability exists due to input validation error when processing directory traversal sequences. A remote attacker can send a specially crafted HTTP request and read arbitrary files on the system.
3) Resource exhaustion (CVE-ID: CVE-2024-47874)
CWE-ID: CWE-400 - Resource exhaustion
CVSSv4: 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
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to application treats multipart/form-data parts without a filename as text form fields and buffers those in byte strings with no size limit. A remote attacker can trigger resource exhaustion and perform a denial of service (DoS) attack.
4) Allocation of Resources Without Limits or Throttling (CVE-ID: CVE-2025-54121)
CWE-ID: CWE-770 - Allocation of Resources Without Limits or Throttling
CVSSv4: 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:U/U:Green
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to when parsing a multi-part form with large files (greater than the default max spool size) starlette will block the main thread to roll the file over to disk. This blocks the event thread which means the application can't accept new connections. The UploadFile code has a minor bug where instead of just checking for self._in_memory, the logic should also check if the additional bytes will cause a rollover. A remote attacker can the vulnerability and perform a denial of service (DoS) attack.
Remediation
Install update from vendor's website.