CyberChef: Prototype pollution in Series Chart operation

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

CyberChef is a web app for encryption, encoding, compression, and data analysis. Prior to 11.2.0, the Series Chart operation accepts __proto__ as a key while parsing user-supplied CSV, allowing prototype pollution that can be chained with operations such as Parse UDP to inject malicious JavaScript into HTML output. This issue is fixed in version 11.2.0.

Source published

8 Jul 2026 14:58:38 UTC

Source modified

8 Jul 2026 16:12:28 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 3.1 · 5.0 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CyberChef is a web app for encryption, encoding, compression, and data analysis. Prior to 11.2.0, the Series Chart operation accepts __proto__ as a key while parsing user-supplied CSV, allowing prototype pollution that can be chained with operations such as Parse UDP to inject malicious JavaScript into HTML output. This issue is fixed in version 11.2.0.

Source published

Jul 8, 2026, 2:58:38 PM (timezone not stated)

Source modified

Jul 8, 2026, 4:12:28 PM (timezone not stated)

Observed here

7 Nov 2026 12:38:04 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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EUVD CVSS 3.1 · 5.0 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CyberChef is a web app for encryption, encoding, compression, and data analysis. Prior to 11.2.0, the Series Chart operation accepts __proto__ as a key while parsing user-supplied CSV, allowing prototype pollution that can be chained with operations such as Parse UDP to inject malicious JavaScript into HTML output. This issue is fixed in version 11.2.0.

Source published

8 Jul 2026 16:16:31 UTC

Source modified

25 Oct 2026 20:10:00 UTC

Observed here

27 Oct 2026 15:15:28 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 5.0 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

On 5 June 2026 CyberChef received a security vulnerability report from @hyuunnn detailing a vulnerability in the Series Chart operation, where malicious input could result in prototype pollution of the data structures outputted from the operation. Other operations following Series Chart could have their behaviour manipulated by the attacker-controlled prototype, for example, injecting malicious content into their HTML output. In this case, a demonstration was provided that chained the Series Chart operation with the Parse UDP operation to cause attacker controlled JavaScript to be executed. ## Details When the Series Chart operation parses user-supplied CSV, it accepts `__proto__` as a key and uses it to pollute the object. The objToTbale function in src/core/lib/Protocol.mjs, used in a number of IP parsing operations, renders data items within `<td>` tags without escaping. These bugs can be chained to produce an XSS vulnerability. **Proof of Concept** [https://gchq.github.io/CyberChef/#recipe=Series_chart('CRLF','Comma','',1,'')Parse_UDP('Raw')&input=X19wcm90b19fLDxpbWcgc3JjPXggb25lcnJvcj1hbGVydChkb2N1bWVudC5kb21haW4pPiwx](https://gchq.github.io/CyberChef/#recipe=Series_chart('CRLF','Comma','',1,'')Parse_UDP('Raw')&input=X19wcm90b19fLDxpbWcgc3JjPXggb25lcnJvcj1hbGVydChkb2N1bWVudC5kb21haW4pPiwx) Encoded input data is: ``` __proto__,<img src=x onerror=alert(document.domain)>,1 ``` ### Impact Objects with attacker controlled prototypes could be processed by CyberChef operations. This enabled control of the output of some operations, and in particular, the ability to insert malicious JavaScript into the output of the Parse UDP operation. ### Patches This has been patched in release v11.2.0. ### Workarounds No workarounds are available. Users must upgrade to CyberChef v11.2.0.

Source published

24 Sep 2026 19:24:30 UTC

Source modified

24 Sep 2026 19:45:04 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Publisher rating · MODERATE