CVE-2026-33036

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Source
https://cve.org/CVERecord?id=CVE-2026-33036
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-33036.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-33036
Aliases
Downstream
CGA (63)
CLEANSTART (10)
CLSA (6)
DEBIAN (1)
ECHO (1)
MINI (16)
openSUSE (2)
ROOT (1)
UBUNTU (1)
Related
openSUSE (2)
Published
2026-03-20T05:17:03Z
Modified
2026-10-21T02:30:22Z
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
fast-xml-parser affected by numeric entity expansion bypassing all entity expansion limits (incomplete fix for CVE-2026-26278)
Details

fast-xml-parser allows users to process XML from JS object without C/C++ based libraries or callbacks. Versions 4.0.0-beta.3 through 5.5.5 contain a bypass vulnerability where numeric character references (&#NNN;, &#xHH;) and standard XML entities completely evade the entity expansion limits (e.g., maxTotalExpansions, maxExpandedLength) added to fix CVE-2026-26278, enabling XML entity expansion Denial of Service. The root cause is that replaceEntitiesValue() in OrderedObjParser.js only enforces expansion counting on DOCTYPE-defined entities while the lastEntities loop handling numeric/standard entities performs no counting at all. An attacker supplying 1M numeric entity references like A can force ~147MB of memory allocation and heavy CPU usage, potentially crashing the process—even when developers have configured strict limits. This issue has been fixed in version 5.5.6.

Database specific 
{
    "cna_assigner":  "GitHub_M",
    "cwe_ids":  [
        "CWE-776"
    ],
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33036.json"
}
References

Affected packages

Git / github.com/naturalintelligence/fast-xml-parser

Affected ranges

Type
GIT
Repo
https://github.com/naturalintelligence/fast-xml-parser
Events
Introduced
bf5d224185c206c09f5e9732aa132d5ad3458336
Fixed
870043e75e78545192bc70950c6286d36c7cdf23
Introduced
267d2df9bc9a13f8cf01f1755e97c62f8977379c
Fixed
bd26122c838e6a55e7d7ac49b4ccc01a49999a01
Database specific
Show details 
{
    "extracted_events":  [
        {
            "cpe":  "cpe:2.3:a:naturalintelligence:fast-xml-parser:*:*:*:*:*:*:*:*",
            "range":  [
                {
                    "introduced":  "4.0.1"
                },
                {
                    "fixed":  "5.5.6"
                }
            ],
            "source":  "CPE_RANGE"
        },
        {
            "cpe":  "cpe:2.3:a:naturalintelligence:fast-xml-parser:4.0.0:-:*:*:*:*:*:*",
            "range":  [
                {
                    "introduced":  "4.0.0-NA"
                },
                {
                    "last_affected":  "4.0.0-NA"
                }
            ],
            "source":  "CPE_STRING"
        },
        {
            "range":  [
                {
                    "fixed":  "bd26122c838e6a55e7d7ac49b4ccc01a49999a01"
                }
            ],
            "source":  "REFERENCES_COMMIT"
        },
        {
            "original_tag":  "v5.5.6",
            "range":  [
                {
                    "fixed":  "870043e75e78545192bc70950c6286d36c7cdf23"
                }
            ],
            "source":  "REFERENCES_TAG"
        }
    ]
}

Affected versions

4.*
4.0.0-NA
v4.*
v4.0.1
v4.0.10
v4.0.11
v4.0.12
v4.0.13
v4.0.14
v4.0.15
v4.0.2
v4.0.4
v4.0.5
v4.0.6
v4.0.7
v4.0.8
v4.0.9
v4.1.0
v4.1.1
v4.1.2
v4.1.3
v4.1.4
v4.2.0
v4.2.3
v4.2.4
v4.2.5
v4.2.6
v4.2.7
v4.3.0
v4.3.1
v4.3.2
v4.3.3
v4.3.4
v4.3.5
v4.3.6
v4.4.0
v4.4.1
v4.5.0
v4.5.1
v4.5.2
v5.*
v5.0.0
v5.0.2
v5.0.4
v5.0.6
v5.0.7
v5.0.9
v5.1.0
v5.2.0
v5.2.1
v5.2.2
v5.2.3
v5.2.5
v5.3.0
v5.3.1
v5.3.2
v5.3.3
v5.3.4
v5.3.5
v5.3.6
v5.3.7
v5.3.8
v5.3.9
v5.4.0
v5.4.1
v5.4.2
v5.5.0
v5.5.1
v5.5.2
v5.5.3
v5.5.4
v5.5.5

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-33036.json"