CVE-2023-34241

CUPS vulnerable to use-after-free in cupsdAcceptClient()

HIGH
7.1
CVSS Score
Published: June 22, 2023 at 10:39 PM UTC
Updated: June 17, 2026 at 06:03 AM UTC
4 products affected across 4 vendorsmacOSDebian LinuxFedora

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Severity
HIGH7.1
Exploit prediction
EPSS 1%
SSVC
PoC

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 11.7.912.0.0 ≤ v < 12.6.813.0 ≤ v < 13.5
Affected range stops below 11.7.9, so it looks safe — our inference, not a vendor statement
Affected range stops below 12.6.8, so it looks safe — our inference, not a vendor statement
Affected range stops below 13.5, so it looks safe — our inference, not a vendor statement
v < 2.4.62.2.0 ≤ v < 2.4.6
Affected range stops below 2.4.6, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-416

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