# CVE-2025-47911: net/html DoS — Fixed in 0.45.0
🐹
🐹 Go
Not in CISA KEV
MEDIUM severity
# CVE-2025-47911 — net/html
MEDIUM
CVE-2025-47911 is a medium-severity (CVSS 5.3) vulnerability in golang.org/x/net/html. A fix is available for golang.org/x/net/html — see the affected versions and patch details below.
golang.org/x/net/html has a Quadratic Parsing Complexity issue
Also known as[GHSA-w4gw-w5jq-g9jh](/vulnerability/GHSA-w4gw-w5jq-g9jh)GO-2026-4440
Published
Feb 5, 2026
Updated
Oct 28, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Nov 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS)
## Exploitation Status
### No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-47911.
## EPSS Exploitation Probability
[via FIRST.org ↗](https://www.first.org/epss/)
0.6%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs47th percentile — riskier than 47% of all scored CVEsHighest risk
0.00%0.35%0.71%1.06%0.0%0.6%May 26Sep 26Nov 26
Probability of exploitation in the next 30 days, from [FIRST.org EPSS](https://www.first.org/epss/).
## How urgent is this, really
## Where this sits among everything scored
## Real-World Exposure
1 pkg affected
🐹`golang.org/x/net/html`
Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
## Description
The html.Parse function in golang.org/x/net/html has quadratic parsing complexity when processing certain inputs, which can lead to denial of service (DoS) if an attacker provides specially crafted HTML content.
## Affected Packages
1 total 1 fixed
Ecosystem
Package
Vulnerable range
Fix
🐹Go
`golang.org/x/net/html`
all versions
0.45.0`go get golang.org/x/net/html@v0.45.0`
## Affected Products
1 product · 1 configurations
Application
`html`go
< 0.45.0
range
## Detection & mitigation playbook
Open-source dependency
1. ### Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for golang.org/x/net/html, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
2. ### Fix
Update golang.org/x/net/html to 0.45.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-47911 is resolved across your whole dependency graph.
3. ### Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
## Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Red HatModerate
Moderate: The \`golang.org/x/net/html\` package, used across various Red Hat products, is vulnerable to a denial of service due to quadratic parsing complexity in its \`html.Parse\` function. An attacker providing specially crafted HTML content could exploit this flaw, leading to resource exhaustion and service…
Product
Fixed in
Advisory
Cert Manager support for Red Hat OpenShift release 1.17
`cert-manager/jetstack-cert-manager-acmesolver-rhel9:1791371080`
[RHSA-2026:82304](https://access.redhat.com/errata/RHSA-2026:82304)
Cert Manager support for Red Hat OpenShift release 1.17
`cert-manager/cert-manager-operator-rhel9:1791788287`
[RHSA-2026:82322](https://access.redhat.com/errata/RHSA-2026:82322)
Cert Manager support for Red Hat OpenShift release 1.18
`cert-manager/cert-manager-istio-csr-rhel9:1791459759`
[RHSA-2026:82354](https://access.redhat.com/errata/RHSA-2026:82354)
Cluster Observability Operator 1.5
`cluster-observability-operator/distributed-tracing-console-plugin-pf4-rhel9:1782840519`
[RHSA-2026:34342](https://access.redhat.com/errata/RHSA-2026:34342)
OpenShift API for Data Protection 1.6
`oadp/oadp-velero-rhel9:1784058822`
[RHSA-2026:43692](https://access.redhat.com/errata/RHSA-2026:43692)
Red Hat Hardened Images
`golang1-26-main-1.26.2-1.hum1`
[RHSA-2026:7291](https://access.redhat.com/errata/RHSA-2026:7291)
Red Hat Hardened Images
`golang1-25-main-1.25.9-1.hum1`
[RHSA-2026:7385](https://access.redhat.com/errata/RHSA-2026:7385)
Red Hat Openshift Data Foundation 4.22
`odf4/cephcsi-rhel9:1782932114`
[RHSA-2026:37387](https://access.redhat.com/errata/RHSA-2026:37387)
## Frequently Asked Questions
The html.Parse function in golang.org/x/net/html has quadratic parsing complexity when processing certain inputs, which can lead to denial of service (DoS) if an attacker provides specially crafted HTML content.
O3 Security · Impact-Aware SCA
### Is CVE-2025-47911 in your dependencies?
Find it across Go, including transitive dependencies.
[Scan my dependencies](/book-demo) [How O3 SCA works](/impact-aware-sca)