Use-after-free from a comparator that answers inconsistently
Published Sources: OSV
What is affected, what to do
`OrderedSkipList`, `SkipSet` and `SkipMap` can free a node that is still linked when a `Comparator` or `Ord` implementation gives different answers for the same pair of values during one mutating call. A later call reads the freed memory (CWE-416).
The available sources name no fixed version. Check the vendor guidance in the references below.
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CVSS v3
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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
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
`OrderedSkipList`, `SkipSet` and `SkipMap` can free a node that is still linked when a `Comparator` or `Ord` implementation gives different answers for the same pair of values during one mutating call. A later call reads the freed memory (CWE-416). A safe `impl Ord` with the default comparator is enough to reach it. The mutating traversals record a precursor at each level: the last node whose link points at a node comparing not-`Less` than the target. The splice code assumes every recorded precursor's link points at or past the final position. If a later comparison reports one of those nodes as `Less`, the walk steps past it and the assumption breaks. Removals such as `take_first`, `take` and `remove` then rewire the wrong link and free the target while its real predecessor still points at it. `insert` builds crossed links and wrong skip distances from the same precursors. A comparator that is a pure function of its two arguments cannot trigger this, even if it is not transitive. The trigger is a stateful or non-deterministic implementation, for example one that reads a counter, a cache, a clock or a random source. The flaw was corrected in 1.3.0. The mutating traversals track the link target of the lowest recorded precursor and panic with "comparator does not implement a total order" when a `Less` answer contradicts an earlier one. Every splice site also checks its precursors before the first write. Each detected contradiction panics before any link, value or length changes, so the collection stays valid and safe to drop.