rsyslog RainerScript replace() Heap Overflow (DoS)
CVE-2026-78002 Published on August 27, 2026
Rsyslog: rsyslog: denial of service via heap buffer overflow in rainerscript replace() function
A flaw was found in rsyslog. An unauthenticated remote attacker can trigger a heap buffer overflow in the RainerScript `replace()` function by sending specially crafted syslog messages. This vulnerability arises from an incorrect buffer size calculation during string replacement, causing memory corruption. Successful exploitation can lead to a denial of service (DoS) for the affected system.
Vulnerability Analysis
CVE-2026-78002 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Timeline
Reported to Red Hat.
Made public. 5 days later.
Weakness Type
Incorrect Calculation of Buffer Size
The software does not correctly calculate the size to be used when allocating a buffer, which could lead to a buffer overflow.
Products Associated with CVE-2026-78002
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