Libevent prior 2.1.13/2.2.2-alpha Event Tagging event_tagging.c evtag_unmarshal_header integer overflow

Summaryinfo

A vulnerability categorized as problematic has been discovered in Libevent. This vulnerability affects the function evtag_unmarshal_header of the file event_tagging.c of the component Event Tagging. Executing a manipulation can lead to integer overflow. The identification of this vulnerability is CVE-2026-63384. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability classified as problematic was found in Libevent. This vulnerability affects the function evtag_unmarshal_header of the file event_tagging.c of the component Event Tagging. The manipulation with an unknown input leads to a integer overflow vulnerability. The CWE definition for the vulnerability is CWE-190. The product 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. As an impact it is known to affect availability. CVE summarizes:

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has an incorrect integer conversion in event_tagging.c when evtag_unmarshal_header uses evtag_decode_int to decode an attacker-controlled uint32 payload length and returns it as a signed int. Values above INT_MAX become negative or truncated, and evtag_unmarshal_string can use the converted value in allocation sizing, producing a wrapped large allocation request and denial of service. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

The advisory is available at github.com. This vulnerability was named CVE-2026-63384 since 07/16/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Technical details are known, but there is no available exploit.

Upgrading to version 2.1.13 or 2.2.2-alpha eliminates this vulnerability.

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Productinfo

Name

• Libevent

Website

• Product: https://github.com/libevent/libevent/

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