CVE-2026-49855

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Source
https://cve.org/CVERecord?id=CVE-2026-49855
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-49855.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-49855
Aliases
Downstream
Related
Published
2026-07-14T20:45:02.982Z
Modified
2026-07-18T03:42:06.675919776Z
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
tornado AsyncHTTPClient accumulates decompressed chunks without size limit (gzip bomb)
Details

Tornado is a Python web framework and asynchronous networking library. Prior to 6.5.6, Tornado gzip decompression routines processed limited-size chunks but did not enforce an overall limit on accumulated decompressed chunks, allowing a malicious server accessed by SimpleAsyncHTTPClient or an HTTPServer configured with decompress_request=True to consume effectively unlimited memory. This issue is fixed in version 6.5.6.

Database specific 
{
    "cwe_ids": [
        "CWE-409"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/49xxx/CVE-2026-49855.json",
    "cna_assigner": "GitHub_M"
}
References

Affected packages

Git / github.com/tornadoweb/tornado

Affected ranges

Type
GIT
Repo
https://github.com/tornadoweb/tornado
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
ff808b33adc52d89a549376a5e3628e92abbc8ff
Database specific 
{
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "fixed": "6.5.6"
        }
    ],
    "source": [
        "AFFECTED_FIELD",
        "REFERENCES"
    ]
}

Affected versions

v1.*
v1.0.0
v1.1.0
v1.2.0
v2.*
v2.0.0
v2.1.0
v2.1.1
v2.2.0
v2.3.0
v3.*
v3.0.0
v3.0.1
v3.1.0
v3.2.0
v3.2.0b1
v3.2.0b2
v4.*
v4.0.0
v4.0.0b1
v4.0.0b2
v4.0.0b3
v4.1.0
v4.1.0b1
v4.1.0b2
v4.2.0
v4.2.0b1
v4.3.0
v4.3.0b1
v4.3.0b2
v4.4.0
v4.4.0b1
v4.4.1
v4.5.0
v4.5.1
v5.*
v5.0.0
v5.1.0
v6.*
v6.0.0
v6.0.0b1
v6.1.0
v6.1.0b1
v6.1.0b2
v6.2.0
v6.2.0b1
v6.2.0b2
v6.3.0
v6.3.0b1
v6.3.1
v6.4.0
v6.4.0b1
v6.4.1
v6.5.0
v6.5.0b1
v6.5.1
v6.5.2
v6.5.3
v6.5.4
v6.5.5

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-49855.json"