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OpenAdvisories
High ALAS2-2026-3902 2 CVEs

Important: libevent security update (Amazon Linux 2)

Published Aug 31, 2026 · Updated Sep 14, 2026

Summary

Package updates are available for Amazon Linux 2 that fix the following vulnerabilities: CVE-2026-63384: 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. CVE-2026-63383: 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.

Fixed packages 4

ReleasePackageFixed in
Amazon Linux · 2 libevent 0:2.0.21-4.amzn2.0.4
Amazon Linux · 2 libevent-debuginfo 0:2.0.21-4.amzn2.0.4
Amazon Linux · 2 libevent-devel 0:2.0.21-4.amzn2.0.4
Amazon Linux · 2 libevent-doc 0:2.0.21-4.amzn2.0.4

Vulnerabilities 2

  • High 8.7

    Libevent: decode_tag_internal() can lead to out-of-bounds read

    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 …

  • High 8.7

    Libevent: `evtag_unmarshal_header()` decodes a wire `uint32` length into a signed `int` return value.

    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…

References

  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-63383.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-63384.html