CVE-2025-47911VulnerabilityPublished 5 Feb 2026Updated 12 Feb 2026

CVE-2025-47911: golang.org/x/net/html · Uncontrolled Resource Consumption

Affects golang.org/x/net/htmlSource CVE Database V5

Not known to be exploited · CVSS 5.3 Medium : upgrade to 0.45.0 when convenient.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

5.3Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.5% chance of exploitation in 30 days – higher than 46% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 0.45.0

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 5 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade golang.org/x/net/html to 0.45.0.

Affected software

Product	Affected	Fixed in
golang.org/x/netgolang.org/x/net/html	Affected <0.45.0	Fixed in 0.45.0
Gogolang.org/x/net/html`pkg:golang/golang.org/x/net/html`Other threats	Affected =0	Fixed in–
Gogolang.org/x/net/html`pkg:golang/golang.org/x/net/html`Other threats	Affected <0.45.0	Fixed in 0.45.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

1. Monitor golang.org/x/net/html package updates closely and apply patches promptly once available to address the quadratic parsing complexity. 2. Implement input validation and sanitization to reject or limit the size and complexity of HTML inputs before parsing. 3. Employ resource usage limits such as CPU timeouts, memory caps, or process isolation (e.g., containerization) to contain the impact of potential DoS attempts. 4. Use application-layer firewalls or rate-limiting mechanisms to detect and block suspicious traffic patterns that may indicate exploitation attempts. 5. Conduct code audits and dependency reviews to identify all applications using the vulnerable package and prioritize remediation accordingly. 6. Consider alternative HTML parsing libraries with better performance characteristics if immediate patching is not feasible. 7. Enhance logging and monitoring to detect unusual spikes in resource consumption that could signal exploitation attempts. 8. Educate development and operations teams about this vulnerability to ensure awareness and rapid response.

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.

Impact

For European organizations, the primary impact of CVE-2025-47911 is the risk of denial of service attacks against applications that utilize the vulnerable html.Parse function. This can affect web servers, API endpoints, microservices, and other software components written in Go that process HTML content. Service disruptions can lead to operational downtime, loss of customer trust, and potential financial losses, especially for critical infrastructure or high-availability services. Organizations in sectors such as finance, telecommunications, government, and cloud service providers are particularly vulnerable due to their reliance on robust and continuous service availability. Additionally, the vulnerability could be exploited as part of a larger attack chain to degrade service quality or as a distraction while other attacks are conducted. The lack of authentication or user interaction requirements lowers the barrier for attackers, increasing the likelihood of exploitation attempts. However, since no known exploits are currently active, the immediate risk is moderate but warrants proactive mitigation.

CWE-400Uncontrolled Resource Consumption (opens in a new tab)
Class weaknessLikelihood of exploit: High
The product does not properly control the allocation and maintenance of a limited resource.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design
Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place.
Architecture and Design
Mitigation of resource exhaustion attacks requires that the target system either: recognizes the attack and denies that user further access for a given amount of time, or; uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed.
Architecture and Design
Ensure that protocols have specific limits of scale placed on them.
OWASP Cheat Sheets
File Upload (opens in a new tab)
OWASP ASVS 4.0.3
V12.1.1 (opens in a new tab)
Attack patterns
XML Ping of the Death (opens in a new tab)
Regular Expression Exponential Blowup (opens in a new tab)
Sustained Client Engagement (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 13 Feb 2026, 06:48 UTC

WeaknessesCWE-400

Technical details

References

Community reviews

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