CUPS vulnerable to use-after-free in cupsdAcceptClient()
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 2.4.6
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: poc
- Automatable: yes
- Technical impact: partial
Summary
OpenPrinting CUPS is a standards-based, open source printing system for Linux and other Unix-like operating systems. Starting in version 2.0.0 and prior to version 2.4.6, CUPS logs data of free memory to the logging service AFTER the connection has been closed, when it should have logged the data right before. This is a use-after-free bug that impacts the entire cupsd process. The exact cause of this issue is the function `httpClose(con->http)` being called in `scheduler/client.c`. The problem is that httpClose always, provided its argument is not null, frees the pointer at the end of the call, only for cupsdLogClient to pass the pointer to httpGetHostname. This issue happens in function `cupsdAcceptClient` if LogLevel is warn or higher and in two scenarios: there is a double-lookup for the IP Address (HostNameLookups Double is set in `cupsd.conf`) which fails to resolve, or if CUPS is compiled with TCP wrappers and the connection is refused by rules from `/etc/hosts.allow` and `/etc/hosts.deny`. Version 2.4.6 has a patch for this issue.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: poc · Automatable: yes · Technical impact: partial
- Record last updated
Affected versions
- OpenPrinting cups
From 2.0.0 · fixed in 2.4.6