CVE-2026-34230

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Source
https://cve.org/CVERecord?id=CVE-2026-34230
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-34230.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2026-34230
Aliases
Downstream
Related
Published
2026-04-02T16:41:21.095Z
Modified
2026-04-09T18:29:19.945306420Z
Severity
  • 5.3 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L CVSS Calculator
Summary
Rack: Quadratic complexity in Rack::Utils.select_best_encoding via wildcard Accept-Encoding header
Details

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Utils.selectbestencoding processes Accept-Encoding values with quadratic time complexity when the header contains many wildcard (*) entries. Because this method is used by Rack::Deflater to choose a response encoding, an unauthenticated attacker can send a single request with a crafted Accept-Encoding header and cause disproportionate CPU consumption on the compression middleware path. This results in a denial of service condition for applications using Rack::Deflater. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.

Database specific 
{
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
        "CWE-400",
        "CWE-407"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34230.json"
}
References

Affected packages

Git / github.com/rack/rack

Affected ranges

Type
GIT
Repo
https://github.com/rack/rack
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
f2af0c8f869193fa7bb7d20b619b3003418e1055
Database specific 
{
    "versions": [
        {
            "introduced": "0"
        },
        {
            "fixed": "2.2.23"
        }
    ]
}
Type
GIT
Repo
https://github.com/rack/rack
Events
Introduced
572a42a705b423ce98ef4e81435d4f60fb0ae53d
Fixed
ae8431120e66e92d1885ab8ec0a553d9cad5ec13
Database specific 
{
    "versions": [
        {
            "introduced": "3.0.0.beta1"
        },
        {
            "fixed": "3.1.21"
        }
    ]
}
Type
GIT
Repo
https://github.com/rack/rack
Events
Introduced
b68251c03788ff39d4a4b25424df7360426e4afd
Fixed
e1f22fdbe99afd2126b6fbf05bb12399359574b7
Database specific 
{
    "versions": [
        {
            "introduced": "3.2.0"
        },
        {
            "fixed": "3.2.6"
        }
    ]
}

Affected versions

0.*
0.1
0.2
0.3
1.*
1.0
1.3.0
1.3.0.beta
1.3.0.beta2
1.4.0
1.4.1
1.5.0
1.5.1
1.6.0.beta
2.*
2.0.0
2.0.0.alpha
2.0.0.rc1
2.0.1
2.1.0
2.2.0
2.2.3
2.2.4
3.*
3.0.0
3.0.0.beta1
3.0.0.rc1
v2.*
v2.2.1
v2.2.10
v2.2.11
v2.2.12
v2.2.13
v2.2.14
v2.2.15
v2.2.16
v2.2.17
v2.2.18
v2.2.19
v2.2.2
v2.2.20
v2.2.21
v2.2.22
v2.2.5
v2.2.6
v2.2.6.1
v2.2.6.2
v2.2.7
v2.2.8
v2.2.9
v3.*
v3.1.0
v3.1.10
v3.1.11
v3.1.12
v3.1.13
v3.1.14
v3.1.15
v3.1.16
v3.1.17
v3.1.18
v3.1.19
v3.1.2
v3.1.20
v3.1.3
v3.1.4
v3.1.5
v3.1.6
v3.1.7
v3.1.8
v3.1.9
v3.2.0
v3.2.1
v3.2.2
v3.2.3
v3.2.4
v3.2.5

Database specific

source 
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-34230.json"