Not ratedosv:RUSTSEC-2026-0408

    Aliasing violations in splice, mutable iteration and cursors

    Published Sources: OSV

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    Priority

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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?

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    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.

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    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.

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    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.

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    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.

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    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.

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    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    Four code paths create a pointer whose permission is later revoked, then write through it. Miri reports each as undefined behaviour under both the Tree Borrows and Stacked Borrows aliasing models (CWE-758). All four are reachable from safe code with standard Ord types.

    1. Splice back-pointer. split_off, split_off_index and append stored the first spliced node's prev pointer from a reference to the head, then wrote through that same reference, invalidating the stored pointer. A later pop_first or pop_front writes through it. This affects all four collections.
    2. SkipMap::range_mut back pointer. With an Included or Excluded upper bound, the back pointer came from a shared reference. next_back hands out &mut V through it, and writing to that value is undefined behaviour.
    3. IterMut::next_back reads a yielded node. In SkipList and SkipMap, next_back read the predecessor node even after the front end had yielded it as &mut. The read freezes the caller's reference, and the caller's next write through it is undefined behaviour. This affects iter_mut, values_mut and range_mut used from both ends.
    4. Cursor list pointer. lower_bound_mut and upper_bound_mut on OrderedSkipList and SkipSet (cursor feature) took the cursor's list pointer, then searched through &self. A comparator with interior-mutable state, such as a Cell call counter, wrote to the list's memory through that shared borrow and invalidated the cursor's pointer. The comparator can be a fully consistent order. SkipMap cursors are not affected.

    No miscompilation has been observed in an optimised build. A future compiler may still optimise on the violated aliasing assumptions.

    The flaws were corrected in 1.3.0. Each fix derives the pointer used for mutation from the collection's long-lived allocation pointers, and each has a Miri regression test.

    Source: OSV (Open Source Vulnerabilities)