CVE-2026-63383

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Source
https://cve.org/CVERecord?id=CVE-2026-63383
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63383.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-63383
Aliases
  • GHSA-fj29-64w6-73h6
Downstream
Published
2026-08-20T17:48:24.568Z
Modified
2026-08-22T09:15:56.055151Z
Severity
  • 8.7 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N CVSS Calculator
Summary
Libevent: decode_tag_internal() can lead to out-of-bounds read
Details

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 eventtagging.c when decodetaginternal requests at most five bytes from evbufferpullup 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.

Database specific 
{
    "cwe_ids": [
        "CWE-125"
    ],
    "cna_assigner": "GitHub_M",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63383.json"
}
References

Affected packages

Git / github.com/libevent/libevent

Affected ranges

Type
GIT
Repo
https://github.com/libevent/libevent
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
df3ecad3a040fd6d4fad4287defe113395de6fd7
Fixed
79ddfb460847999b807cba76d04e73891f29c6ee
Fixed
91ed8745eebabdd27592a83d350338a8c4626321
Fixed
e1f9e21887c6b104e206a718385ba3ffc75180cb
Database specific
Show details 
{
    "source": [
        "AFFECTED_FIELD",
        "REFERENCES"
    ],
    "extracted_events": [
        {
            "introduced": "2.2.0-alpha"
        },
        {
            "fixed": "2.2.2-alpha"
        },
        {
            "introduced": "0"
        },
        {
            "fixed": "2.1.13"
        }
    ]
}

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-2.1.10-stable
release-2.1.11-stable
release-2.1.12-stable
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-2.1.9-beta
release-2.2.1-alpha

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63383.json"
vanir_signatures 
[
    {
        "signature_type": "Function",
        "digest": {
            "function_hash": "159443554126248192493229143747497657830",
            "length": 554.0
        },
        "target": {
            "function": "http_check_transfer_encoding_test",
            "file": "test/regress_http.c"
        },
        "source": "https://github.com/libevent/libevent/commit/df3ecad3a040fd6d4fad4287defe113395de6fd7",
        "signature_version": "v1",
        "id": "CVE-2026-63383-09212634",
        "deprecated": false
    },
    {
        "signature_type": "Function",
        "digest": {
            "function_hash": "168865482628713793503789314971219105523",
            "length": 704.0
        },
        "target": {
            "function": "decode_tag_internal",
            "file": "event_tagging.c"
        },
        "source": "https://github.com/libevent/libevent/commit/91ed8745eebabdd27592a83d350338a8c4626321",
        "signature_version": "v1",
        "id": "CVE-2026-63383-1e099809",
        "deprecated": false
    },
    {
        "signature_type": "Line",
        "digest": {
            "threshold": 0.9,
            "line_hashes": [
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                "168570413533780985513641597969239978857"
            ]
        },
        "target": {
            "file": "test/regress_http.c"
        },
        "source": "https://github.com/libevent/libevent/commit/df3ecad3a040fd6d4fad4287defe113395de6fd7",
        "signature_version": "v1",
        "id": "CVE-2026-63383-923050c6",
        "deprecated": false
    },
    {
        "signature_type": "Line",
        "digest": {
            "threshold": 0.9,
            "line_hashes": [
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        },
        "target": {
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        },
        "source": "https://github.com/libevent/libevent/commit/91ed8745eebabdd27592a83d350338a8c4626321",
        "signature_version": "v1",
        "id": "CVE-2026-63383-92598536",
        "deprecated": false
    },
    {
        "signature_type": "Line",
        "digest": {
            "threshold": 0.9,
            "line_hashes": [
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                "37564212311334647331345684303177453724",
                "168570413533780985513641597969239978857"
            ]
        },
        "target": {
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        },
        "source": "https://github.com/libevent/libevent/commit/79ddfb460847999b807cba76d04e73891f29c6ee",
        "signature_version": "v1",
        "id": "CVE-2026-63383-979e5bed",
        "deprecated": false
    },
    {
        "signature_type": "Function",
        "digest": {
            "function_hash": "168865482628713793503789314971219105523",
            "length": 704.0
        },
        "target": {
            "function": "decode_tag_internal",
            "file": "event_tagging.c"
        },
        "source": "https://github.com/libevent/libevent/commit/e1f9e21887c6b104e206a718385ba3ffc75180cb",
        "signature_version": "v1",
        "id": "CVE-2026-63383-bfebe374",
        "deprecated": false
    },
    {
        "signature_type": "Function",
        "digest": {
            "function_hash": "159443554126248192493229143747497657830",
            "length": 554.0
        },
        "target": {
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            "file": "test/regress_http.c"
        },
        "source": "https://github.com/libevent/libevent/commit/79ddfb460847999b807cba76d04e73891f29c6ee",
        "signature_version": "v1",
        "id": "CVE-2026-63383-ebc5ab94",
        "deprecated": false
    },
    {
        "signature_type": "Line",
        "digest": {
            "threshold": 0.9,
            "line_hashes": [
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                "8463618082298884694292563523725245195",
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            ]
        },
        "target": {
            "file": "event_tagging.c"
        },
        "source": "https://github.com/libevent/libevent/commit/e1f9e21887c6b104e206a718385ba3ffc75180cb",
        "signature_version": "v1",
        "id": "CVE-2026-63383-ecf93e73",
        "deprecated": false
    }
]
vanir_signatures_modified 
"2026-08-22T09:15:56Z"