What is CVE-2026-6019?

http.cookies.Morsel.js_output() returns an inline snippet and only escapes " for JavaScript string context. It does not neutralize the HTML parser-sensitive sequence inside the generated script element. Mitigation base64-encodes the cookie value to disallow escaping using cookie value.

How severe is CVE-2026-6019?

CVE-2026-6019 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2026-6019 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (14th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-6019?

CVE-2026-6019 affects Python. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-6019?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-6019 have an EU (EUVD) identifier?

Yes. CVE-2026-6019 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-25079.

When was CVE-2026-6019 published?

CVE-2026-6019 was published on 2026-04-22 and last updated on 2026-06-17.

CVE-2026-6019

CVE-2026-6019 is a medium-severity vulnerability in Python with a CVSS 3.x base score of 6.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-116.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v4: 2.1
EPSS exploit prediction: 0% (14th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-25079
Weakness: CWE-116
Affected product: Python
Published: 2026-04-22
Last modified: 2026-06-17

Description

http.cookies.Morsel.js_output() returns an inline <script> snippet and only escapes " for JavaScript string context. It does not neutralize the HTML parser-sensitive sequence </script> inside the generated script element. Mitigation base64-encodes the cookie value to disallow escaping using cookie value.

Frequently asked questions

What is CVE-2026-6019?: http.cookies.Morsel.js_output() returns an inline <script> snippet and only escapes " for JavaScript string context. It does not neutralize the HTML parser-sensitive sequence </script> inside the generated script element. Mitigation base64-encodes the cookie value to disallow escaping using cookie value.
How severe is CVE-2026-6019?: CVE-2026-6019 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-6019 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (14th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-6019?: CVE-2026-6019 affects Python. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-6019?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-6019 have an EU (EUVD) identifier?: Yes. CVE-2026-6019 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-25079.
When was CVE-2026-6019 published?: CVE-2026-6019 was published on 2026-04-22 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:python:python:*:*:*:*:*:*:*:*

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Threat intelligence

Threat-intel indicators referencing this CVE:

41.63.62.103 (ipv4-addr)
203.192.232.180 (ipv4-addr)
149.86.233.213 (ipv4-addr)
141.109.168.26 (ipv4-addr)
141.109.168.107 (ipv4-addr)
125.212.235.194 (ipv4-addr)
120.28.109.188 (ipv4-addr)
103.61.123.132 (ipv4-addr)