How severe is CVE-2026-2266?

CVE-2026-2266 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2026-2266 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-2266?

CVE-2026-2266 affects Github Enterprise Server. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-2266?

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

Does CVE-2026-2266 have an EU (EUVD) identifier?

Yes. CVE-2026-2266 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-10792.

When was CVE-2026-2266 published?

CVE-2026-2266 was published on 2026-03-10 and last updated on 2026-06-17.

CVE-2026-2266

CVE-2026-2266 is a medium-severity vulnerability in Github Enterprise Server with a CVSS 3.x base score of 5.4. 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-79.

Key facts

Severity: Medium (CVSS 3.x base score 5.4)
CVSS v4: 7.4
EPSS exploit prediction: 0% (7th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-10792
Weakness: CWE-79
Affected product: Github Enterprise Server
Published: 2026-03-10
Last modified: 2026-06-17

Description

An improper neutralization of input vulnerability was identified in GitHub Enterprise Server that allowed DOM-based cross-site scripting via task list content. The task list content extraction logic did not properly re-encode browser-decoded text nodes before rendering, allowing user-supplied HTML to be injected into the page. An authenticated attacker could craft malicious task list items in issues or pull requests to execute arbitrary scripts in the context of another user's browser session. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.20 and was fixed in versions 3.18.6 and 3.19.3. This vulnerability was reported via the GitHub Bug Bounty program.

Frequently asked questions

What is CVE-2026-2266?: An improper neutralization of input vulnerability was identified in GitHub Enterprise Server that allowed DOM-based cross-site scripting via task list content. The task list content extraction logic did not properly re-encode browser-decoded text nodes before rendering, allowing user-supplied HTML to be injected into the page. An authenticated attacker could craft malicious task list items in issues or pull requests to execute arbitrary scripts in the context of another user's browser session. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.20 and was fixed in versions 3.18.6 and 3.19.3. This vulnerability was reported via the GitHub Bug Bounty program.
How severe is CVE-2026-2266?: CVE-2026-2266 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-2266 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-2266?: CVE-2026-2266 affects Github Enterprise Server. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-2266?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-2266 have an EU (EUVD) identifier?: Yes. CVE-2026-2266 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-10792.
When was CVE-2026-2266 published?: CVE-2026-2266 was published on 2026-03-10 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*

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