CVE-2009-5155
Publication date 26 February 2019
Last updated 18 August 2025
Ubuntu priority
Cvss 3 Severity Score
Description
In the GNU C Library (aka glibc or libc6) before 2.28, parse_reg_exp in posix/regcomp.c misparses alternatives, which allows attackers to cause a denial of service (assertion failure and application exit) or trigger an incorrect result by attempting a regular-expression match.
Status
| Package | Ubuntu Release | Status | 
|---|---|---|
| gnulib | 25.10 questing | 
                                Not affected 
                                
                               | 
| 25.04 plucky | 
                                Not affected 
                                
                               | |
| 24.04 LTS noble | 
                                Not affected 
                                
                               | |
| 22.04 LTS jammy | 
                                Not affected 
                                
                               | |
| 20.04 LTS focal | 
                                Not affected 
                                
                               | |
| 18.04 LTS bionic | 
                                Vulnerable 
                                
                               | |
| 16.04 LTS xenial | 
                                Vulnerable 
                                
                               | |
| 14.04 LTS trusty | Not in release | |
| eglibc | 25.10 questing | Not in release | 
| 25.04 plucky | Not in release | |
| 24.04 LTS noble | Not in release | |
| 22.04 LTS jammy | Not in release | |
| 20.04 LTS focal | Not in release | |
| 18.04 LTS bionic | Not in release | |
| 16.04 LTS xenial | Not in release | |
| 14.04 LTS trusty | 
                                Vulnerable 
                                
                               | |
| glibc | 25.10 questing | 
                                Not affected 
                                
                               | 
| 25.04 plucky | 
                                Not affected 
                                
                               | |
| 24.04 LTS noble | 
                                Not affected 
                                
                               | |
| 22.04 LTS jammy | 
                                Not affected 
                                
                               | |
| 20.04 LTS focal | 
                                Not affected 
                                
                               | |
| 18.04 LTS bionic | 
                                Vulnerable 
                                
                               | |
| 16.04 LTS xenial | 
                                Fixed 2.23-0ubuntu11.3 
                                
                               | |
| 14.04 LTS trusty | Not in release | 
Severity score breakdown
| Parameter | Value | 
|---|---|
| Base score |  | 
| Attack vector | Network | 
| Attack complexity | Low | 
| Privileges required | None | 
| User interaction | None | 
| Scope | Unchanged | 
| Confidentiality | None | 
| Integrity impact | None | 
| Availability impact | High | 
| Vector | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | 
References
Related Ubuntu Security Notices (USN)
- USN-4954-1
- GNU C Library vulnerabilities
- 14 May 2021