No exploitation reportedFix available

CVE-2026-27136

Q: Is CVE-2026-27136 actively exploited?

Active exploitation of CVE-2026-27136 has not been confirmed. Its EPSS score was 0.2% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2026-27136?

CVE-2026-27136 has a CVSS v3 base score of 6.1 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

No exploitation reported by the sources we read.

Published2026-05-22
Fixed in0.55.0
WeaknessCWE-1021

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Parsing arbitrary HTML which is then rendered using Render can result in an unexpected HTML tree. This can be leveraged to execute XSS attacks in applications that attempt to sanitize input HTML before rendering.

Timeline

dates in UTC

2026-05-2216:16CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-27136?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-27136?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV

Golang net

Branch	Affected	Fixed in	Source
0.55	< 0.55.0	0.55.0	NVD · OSV

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

osbuild-composerAlmaLinux:10all versions · fixed in 165.1-5.el10_2.alma.1and 2 other packages
osbuild-composerAlmaLinux:9all versions · fixed in 165.1-5.el9_8.alma.1and 2 other packages
podmanAlmaLinux:9all versions · fixed in 6:5.8.2-4.el9_8and 4 other packages

Vendor advisories

CVE-2026-27136 Red Hat Product Security1,380 products fixed · 160 known affected
golang.org/x/net/html: golang: golang.org/x/net/html: Cross-Site Scripting via HTML parsing bypass
assisted/agent-preinstall-image-builder-rhel9 as a component of Assisted Installer for Red Hat OpenShift Container Platform 2 · rhai/assisted-installer-agent-rhel9 as a component of Assisted Installer for Red Hat OpenShift Container Platform 2 · rhai/assisted-installer-controller-rhel9 as a component of Assisted Installer for Red Hat OpenShift Container Platform 2 · +157 more
RHSA-2026:87410 Red Hat Product Security3 products fixed
Red Hat Security Advisory: RHOAI 2.25.12 - Red Hat OpenShift AI
RHSA-2026:83702 Red Hat Product Security2 products fixed
Red Hat Security Advisory: OpenShift Container Platform 4.21.39 bug fix and security update
RHSA-2026:84734 Red Hat Product Security7 products fixed
Red Hat Security Advisory: RHOAI 3.4.5 - Red Hat OpenShift AI
RHSA-2026:83013 Red Hat Product Security4 products fixed
Red Hat Security Advisory: Logging for Red Hat OpenShift - 6.0.17
RHSA-2026:82354 Red Hat Product Security4 products fixed
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.18.2

104 more advisories

Full record on NVD

Fix

Update Golang net to 0.55.0
Vendor fix Red Hat Product Security RHSA-2026:87410 · 3 productsFor Red Hat OpenShift AI 2.25.12 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this errata update: https://docs.redhat.com/en/documentation/red_hat_openshift_ai/
Vendor fix Red Hat Product Security RHSA-2026:83702 · 2 productsFor OpenShift Container Platform 4.21 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update: https://docs.redhat.com/en/documentation/openshift_container_platform/4.…
Vendor fix Red Hat Product Security RHSA-2026:84734 · 7 productsFor Red Hat OpenShift AI 3.4.5 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this errata update: https://docs.redhat.com/en/documentation/red_hat_openshift_ai/
Vendor fix Red Hat Product Security RHSA-2026:83013 · 4 productsFor OpenShift Container Platform 4.16 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this errata update: https://docs.redhat.com/en/documentation/openshift_container_platform/4.16/html/relea…
Vendor fix Red Hat Product Security RHSA-2026:82354 · 4 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. The steps to apply the upgraded images are different depending on the installation plan approval policy you used when installing the cert-manager Operator for Red Hat OpenShift. - If t…
Vendor fix Red Hat Product Security RHSA-2026:79320 · 4 productsFor OpenShift Container Platform 4.20 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update: https://docs.redhat.com/en/documentation/openshift_container_platform/4.…

Advisories and patches

pkg.go.devVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CISA-ADPSSVC decisionnone2026-05-22
OpenCVESSVC decisionnone—
CISA-ADPCVSS 3.16.12026-05-22
NVDweakness (CWE)CWE-1021read 2026-10-23
FIRST EPSSEPSS score0.2 %2026-10-22
OSVaffected packages—
Microsoft MSRCadvisory—

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Published: 2026-05-22
Last Modified: 2026-07-23
NVD status: Analyzed
MSRC Title: Invoking duplicate attributes can cause XSS in golang.org/x/net/html

Frequently asked questions

What is CVE-2026-27136?

Is CVE-2026-27136 actively exploited?

Active exploitation of CVE-2026-27136 has not been confirmed. Its EPSS score was 0.2% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-27136?

CVE-2026-27136 has a CVSS v3 base score of 6.1 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

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