Cockpit ILP32 Integer Overflow Enables Unauthorized lastlog Access
CVE-2026-91142 Published on September 18, 2026
Cockpit: cockpit: unauthorized modification of login records via integer overflow
A flaw was found in Cockpit. An authenticated local user with a large user identifier (UID) can cause unauthorized modification and disclosure of login records. On 32-bit systems, an integer overflow during session accounting allows the user's login process to read or overwrite the legacy log entries of other accounts.
Vulnerability Analysis
CVE-2026-91142 is exploitable with local system access, and requires small amount of user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have a small impact on confidentiality and integrity, and no impact on availability.
Timeline
Reported to Red Hat.
Made public. 123 days later.
Weakness Type
Integer Overflow or Wraparound
The software performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control. An integer overflow or wraparound occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may wrap to become a very small or negative number. While this may be intended behavior in circumstances that rely on wrapping, it can have security consequences if the wrap is unexpected. This is especially the case if the integer overflow can be triggered using user-supplied inputs. This becomes security-critical when the result is used to control looping, make a security decision, or determine the offset or size in behaviors such as memory allocation, copying, concatenation, etc.
Products Associated with CVE-2026-91142
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