CVE-2026-63495

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Source

https://cve.org/CVERecord?id=CVE-2026-63495

Import Source

https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63495.json

JSON Data

https://api.osv.dev/v1/vulns/CVE-2026-63495

Aliases

GHSA-qx89-wf2v-vgmx

Downstream

RHSA-2026:41176

UBUNTU-CVE-2026-63495

Published

2026-08-20T17:49:16Z

Modified

2026-09-11T08:36:41Z

Severity

7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator

Summary

Libevent: Unbounded memory accumulation in WebSocket server via fragmented frames

Details

Libevent is an event notification library. From 2.2.0-alpha-dev until 2.2.2-alpha, the libevent WebSocket server in ws.c accumulates fragmented frames in evws->incomplete_frames without enforcing a total message-size limit. An unauthenticated remote client can repeatedly send fragmented WebSocket frames below WS_MAX_RECV_FRAME_SZ with FIN=0, causing the evbuffer to grow without bound until the process or host exhausts memory. This issue is fixed in version 2.2.2-alpha.

Database specific

{
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
        "CWE-400",
        "CWE-770"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63495.json"
}

References

Affected packages

Git / github.com/libevent/libevent

Affected ranges

Type

GIT

Repo

https://github.com/libevent/libevent

Events

Introduced

Fixed

291c4d1cd75695e898030ebd5c4ddf26c094077b

Fixed

df3ecad3a040fd6d4fad4287defe113395de6fd7

Database specific

Show details

{
    "extracted_events": [
        {
            "introduced": "2.2.0-alpha-dev"
        },
        {
            "fixed": "2.2.2-alpha"
        }
    ],
    "source": [
        "AFFECTED_FIELD",
        "REFERENCES"
    ]
}

Affected versions

release-1.*

release-1.1b

release-2.*

release-2.0.1-alpha

release-2.0.10-stable

release-2.0.3-alpha

release-2.0.4-alpha

release-2.0.5-beta

release-2.0.6-rc

release-2.0.7-rc

release-2.0.8-rc

release-2.0.9-rc

release-2.1.1-alpha

release-2.1.2-alpha

release-2.1.3-alpha

release-2.1.4-alpha

release-2.1.5-beta

release-2.1.6-beta

release-2.1.7-rc

release-2.1.8-stable

release-2.2.1-alpha

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63495.json"

vanir_signatures

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vanir_signatures_modified

"2026-09-11T08:36:41Z"