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3.4 KiB
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3.4 KiB
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{"schema_version":"1.7.5","id":"RUSTSEC-2026-0195","published":"2026-06-29T12:00:00Z","modified":"2026-07-02T09:00:04.037478193Z","summary":"Unbounded namespace-declaration allocation in `NsReader` enables memory-exhaustion denial of service","details":"`NsReader` resolves namespaces by calling `NamespaceResolver::push` for every\n`Start`/`Empty` event *before* the event is returned to the caller. `push`\niterated all `xmlns` / `xmlns:*` attributes on the start tag and, for each one,\nappended the prefix bytes to an internal buffer and pushed a `NamespaceBinding`\n(32 bytes on 64-bit) to an internal `Vec`, with no upper bound on the number of\ndeclarations.\n\n## Impact\n\nA start tag with `N` namespace declarations drove roughly `3×` the tag's byte\nsize in `NamespaceResolver` heap, allocated *inside* `quick-xml` before the\n`NsReader` consumer ever received the event and could inspect or reject it. A\nconsumer that bounds its *input* size therefore still cannot bound this\nallocation: an `M`-byte start tag yields on the order of `3 × M` bytes of\nresolver heap the caller never sees.\n\nOn untrusted XML this lets a remote, unauthenticated attacker force large heap\nallocations with a single start tag. With several `NsReader`s running\nconcurrently on independent inputs (a common server pattern), the allocations\nstack and can exhaust process memory, causing the operating system to kill the\nprocess (OOM). This was confirmed against a real-world RPKI relying party (NLnet\nLabs Routinator), where concurrent RRDP validation workers parsing a crafted\n`snapshot.xml` exceeded the memory limit and the process was OOM-killed.\n\n## Affected code paths\n\nConsumers using `NsReader` (which always calls `NamespaceResolver::push` before\nyielding `Start`/`Empty`), or calling `NamespaceResolver::push` directly. A plain\n`Reader` that does not perform namespace resolution is not affected.\n\n## Remediation\n\nUpgrade to `quick-xml >= 0.41.0`. `NamespaceResolver::push` now rejects a start\ntag that declares more than `DEFAULT_MAX_DECLARATIONS_PER_ELEMENT` (256)\nnamespace bindings, returning the new `NamespaceError::TooManyDeclarations`\ninstead of allocating without limit. The limit is configurable via\n`NamespaceResolver::set_max_declarations_per_element` (use `usize::MAX` to\nrestore the previous unbounded behavior), and `NsReader::resolver_mut()` is\nprovided to reach it.\n\nThere is no clean workaround for `NsReader` consumers before 0.41.0, as the\nallocation happens inside the reader with no configuration knob to cap it.","affected":[{"package":{"name":"quick-xml","ecosystem":"crates.io","purl":"pkg:cargo/quick-xml"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0.0.0-0"},{"fixed":"0.41.0"}]}],"ecosystem_specific":{"affected_functions":null,"affects":{"arch":[],"functions":[],"os":[]}},"database_specific":{"categories":["denial-of-service"],"cvss":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","informational":null,"source":"https://github.com/rustsec/advisory-db/blob/osv/crates/RUSTSEC-2026-0195.json"}}],"references":[{"type":"PACKAGE","url":"https://crates.io/crates/quick-xml"},{"type":"ADVISORY","url":"https://rustsec.org/advisories/RUSTSEC-2026-0195.html"},{"type":"REPORT","url":"https://github.com/tafia/quick-xml/issues/970"},{"type":"WEB","url":"https://github.com/tafia/quick-xml/commit/7ca25266e94987210daa864889ab15c9332c8a2a"}],"database_specific":{"license":"CC0-1.0"},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]} |