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Noroxi
NVD / CVE Program· CNA Go

CVE-2026-27136: Invoking duplicate attributes can cause XSS in golang.org/x/net/html

Noroxi assessment

Priority: Monitor (action score 24/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.22% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
  • Fixed version: golang.org/x/net golang.org/x/net/html 0.55.0; azl3 application-gateway-kubernetes-ingress 1.7.7-3 on Azure Linux 3.0 1.7.7-4; azl3 cert-manager 1.12.15-6 on Azure Linux 3.0 1.12.15-8.

Low priority for now. Upgrade to golang.org/x/net golang.org/x/net/html 0.55.0; azl3 application-gateway-kubernetes-ingress 1.7.7-3 on Azure Linux 3.0 1.7.7-4; azl3 cert-manager 1.12.15-6 on Azure Linux 3.0 1.12.15-8 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 6.1 · v3.1—No exploit Fix available
Published
May 22, 2026
Updated
Jul 23, 2026
EPSS
0.2% · 12th percentile

Report tools

JSON

Action score

24

Monitor

Low priority for now.

CVSS
24 / 40 · 6.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-27136

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
golangnet

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Clickjacking protection needs CSP frame-ancestors or X-Frame-Options. Check for free whether your site sends them.

Check security headers

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • golang netbefore 0.55.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Go). Independent of NVD's CPE analysis and usually ahead of it.

  • golang.org/x/net golang.org/x/net/html

    • before 0.55.0affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:10osbuild-composerbefore 165.1-5.el10_2.alma.1165.1-5.el10_2.alma.1
AlmaLinux:10osbuild-composer-corebefore 165.1-5.el10_2.alma.1165.1-5.el10_2.alma.1
AlmaLinux:10osbuild-composer-workerbefore 165.1-5.el10_2.alma.1165.1-5.el10_2.alma.1
AlmaLinux:9osbuild-composerbefore 165.1-5.el9_8.alma.1165.1-5.el9_8.alma.1
AlmaLinux:9osbuild-composer-corebefore 165.1-5.el9_8.alma.1165.1-5.el9_8.alma.1
AlmaLinux:9osbuild-composer-workerbefore 165.1-5.el9_8.alma.1165.1-5.el9_8.alma.1
AlmaLinux:9podmanbefore 6:5.8.2-4.el9_86:5.8.2-4.el9_8
AlmaLinux:9podman-dockerbefore 6:5.8.2-4.el9_86:5.8.2-4.el9_8
AlmaLinux:9podman-pluginsbefore 6:5.8.2-4.el9_86:5.8.2-4.el9_8
AlmaLinux:9podman-remotebefore 6:5.8.2-4.el9_86:5.8.2-4.el9_8
AlmaLinux:9podman-testsbefore 6:5.8.2-4.el9_86:5.8.2-4.el9_8
Debian:12golang-golang-x-netfrom 0—
Debian:14golang-golang-x-netbefore 1:0.55.0-11:0.55.0-1
Gogolang.org/x/netbefore 0.55.00.55.0
openSUSE:Leap 16.0alloybefore 1.17.0-160000.1.11.17.0-160000.1.1
openSUSE:Leap 16.0containerized-data-importer1.65before 1.65.0-160000.3.11.65.0-160000.3.1
openSUSE:Leap 16.0cosignbefore 3.1.1-160000.1.13.1.1-160000.1.1
openSUSE:Leap 16.0glabbefore 1.114.0-bp160.1.11.114.0-bp160.1.1
openSUSE:Leap 16.0grafanabefore 11.6.14+security04-bp160.2.111.6.14+security04-bp160.2.1
openSUSE:Leap 16.0haulerbefore 2.0.1-bp160.1.12.0.1-bp160.1.1
openSUSE:Leap 16.0kubevirt1.8before 1.8.4-160000.1.11.8.4-160000.1.1
openSUSE:Leap 16.0luxbefore 0.24.1-bp160.1.10.24.1-bp160.1.1
openSUSE:Leap 16.0mcphostbefore 0.34.0-160000.2.10.34.0-160000.2.1
openSUSE:Leap 16.0neonmodembefore 1.0.7+git0.346d1d3-bp160.1.11.0.7+git0.346d1d3-bp160.1.1

+96

Same product

golang: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-39821Invoking failure to reject ASCII-only Punycode-encoded labels in golang.org/x/net/idna
    39Monitor
  • CVE-2018-17848The html package (aka x/net/html) through 2018-09-25 in Go mishandles <math><template><mn><b></template>, leading to a "panic: runtime error
    31Monitor
  • CVE-2018-17847The html package (aka x/net/html) through 2018-09-25 in Go mishandles <svg><template><desc><t><svg></template>, leading to a "panic: runtime
    31Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-25680May 22, 2026 · Invoking denial of service when parsing arbitrary HTML in golang.org/x/net/html
    26Monitor
  • ← EarlierCVE-2026-25681May 22, 2026 · Invoking incorrect handling of character references in DOCTYPE nodes in golang.org/x/net/html
    24Monitor
  • Later →CVE-2026-42502May 22, 2026 · Invoking incorrect handling of HTML elements in foreign content in golang.org/x/net/html
    24Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
golang.org/x/net golang.org/x/net/html0.55.0Vendor (CNA)
azl3 application-gateway-kubernetes-ingress 1.7.7-3 on Azure Linux 3.01.7.7-4 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 cert-manager 1.12.15-6 on Azure Linux 3.01.12.15-8 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 cf-cli 8.7.11-5 on Azure Linux 3.08.7.11-6 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 cloud-provider-kubevirt 0.5.1-3 on Azure Linux 3.00.5.1-4 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 cni-plugins 1.4.0-5 on Azure Linux 3.01.4.0-6 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 cni-plugins 1.4.0-6 on Azure Linux 3.01.4.0-6 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 containerd2 2.1.6-2 on Azure Linux 3.02.1.6-3 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 containerized-data-importer 1.62.0-3 on Azure Linux 3.01.62.0-5 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 cri-tools 1.32.0-4 on Azure Linux 3.01.32.0-6 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 dasel 2.8.1-3 on Azure Linux 3.02.8.1-4 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 dasel 2.8.1-4 on Azure Linux 3.02.8.1-4 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 docker-buildx 0.14.0-11 on Azure Linux 3.00.14.0-13 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 docker-compose 2.27.0-9 on Azure Linux 3.02.27.0-11 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 gh 2.62.0-15 on Azure Linux 3.02.62.0-16 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 influxdb 2.7.5-15 on Azure Linux 3.02.7.5-17 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 keda 2.14.1-11 on Azure Linux 3.02.14.1-13 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 kube-vip-cloud-provider 0.0.10-5 on Azure Linux 3.00.0.10-6 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 kubernetes 1.30.10-23 on Azure Linux 3.01.30.10-25 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 kubernetes 1.30.10-25 on Azure Linux 3.01.30.10-25 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 kubevirt 1.7.1-2 on Azure Linux 3.01.7.1-5 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 multus 4.0.2-7 on Azure Linux 3.04.0.2-8 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 packer 1.9.5-13 on Azure Linux 3.01.9.5-14 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 prometheus-adapter 0.12.0-5 on Azure Linux 3.00.12.0-6 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 sriov-network-device-plugin 3.7.0-5 on Azure Linux 3.03.7.0-6 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 sriov-network-device-plugin 3.7.0-6 on Azure Linux 3.03.7.0-6 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 telegraf 1.31.0-19 on Azure Linux 3.01.31.0-21 · CBL-Mariner ReleasesMicrosoft (MSRC)
almalinux:osbuild-composer165.1-5.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)
almalinux:osbuild-composer-core165.1-5.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)
almalinux:osbuild-composer-worker165.1-5.el10_2.alma.1 · AlmaLinux:10Package registry (OSV)

+46

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-256810 days apartInvoking incorrect handling of character references in DOCTYPE nodes in golang.org/x/net/html
    24Monitor
  • CVE-2026-425020 days apartInvoking incorrect handling of HTML elements in foreign content in golang.org/x/net/html
    24Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
low · data or configuration can be modified
Availability
none

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Changed
Confidentiality impact
Low
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-1021 · Improper Restriction of Rendered UI Layers or Frames

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (3 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records