CVE-2026-63383

HighCVSS 8.7/10Last modified Oct 26, 2026

Description

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent can read beyond a contiguous evbuffer region in event_tagging.c when decode_tag_internal requests at most five bytes from evbuffer_pullup but iterates using the full logical buffer length. A fragmented evbuffer containing a six-byte malformed tag can therefore advance past the pullup window and trigger an out-of-bounds read, which can crash a process that decodes attacker-controlled tagged RPC data. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

Metrics

CVSS 4.0 8.7/10CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Weakness enumeration

Affected software

Source: the vendor's advisory (CNA). NVD analysis pending.

VendorProductVersions
libeventlibevent>= 2.2.0-alpha, < 2.2.2-alpha; < 2.1.13

References

Timeline

Published
Aug 20, 2026
Last modified
Oct 26, 2026
NVD status
Awaiting Analysis

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CVE-2026-63383: High severity, CVSS 8.7 | Vulnix