rustls: Allocation of Resources Without Limits or Throttling (ghsa:GHSA-h2v8-394m-p7vv)
Published Sources: Hersteller
What is affected, what to do
Update rustls to version 0.23.46.
Not sure whether and how you are affected? Ask a question about this vulnerability
Metrics
—
Priority
No value is available for this vulnerability.
—
CVSS v3
No value is available for this vulnerability.
—
EPSS score
No value is available for this vulnerability.
Show all metrics
- Severity
- Low
Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 30.00 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- no public PoC known
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- —
- Published
CWE
CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.
Read in glossary- CWE-770
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- Handle the vulnerability in regular vulnerability handling under Art. 21(2)(e) NIS2.
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
Description
Summary
The built-in (but disabled by default) Brotli certificate decoder bounds the output buffer but accepts an input-selected history window. A header of five bytes can specify a 1 GiB window allocation. A peer can abort a process whose allocator cannot satisfy that request. A client must enable Brotli and connect to the peer; a server must enable Brotli and request a client certificate. Neither direction requires a trusted attacker certificate.
Details
rustls calls BrotliDecompress which enables Brotli's large-window extension. rustls applies a limit to certificates, but this applies to the decompressed result, and not to any internal allocations the process requires.
Impact
Client applications that enable the brotli feature will be vulnerable to malicious servers. Server applications that enable the brotli feature and enable client authentication will be vulnerable to malicious clients.
Potential for denial of service due to memory exhaustion from peers sending malicious Brotli-encoded certificates, for applications that enable Brotli decompression.
Acknowledgement
Thanks to OpenAI OutboundDisclosures@openai.com for the disclosure.
Source: GitHub Security Advisories
Affected products
The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.
| Affected versions | Fixed in | ||
|---|---|---|---|
| rust | rustls |
|
|
Vendors and products
Weakness classes (CWE)
CWE-770Allocation of Resources Without Limits or Throttling
Base
The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.
Entry at MITRE CWE-770