{"answers":{"affected":"1 open source package ship an affected version, including zstd-safe.","exploited":"There is no known exploitation of RUSTSEC-2026-0403 in the wild and no public exploit code.","fix":"Upgrade zstd-safe to 8.2.0 or later.","what":"RUSTSEC-2026-0403 is a vulnerability in zstd-safe, published on 16 Oct 2026."},"fix_prompt":"Check this codebase for RUSTSEC-2026-0403 and fix it if it is affected.\n\nWhat it is: RUSTSEC-2026-0403 is a vulnerability in zstd-safe, published on 16 Oct 2026. \nExploitation: There is no known exploitation of RUSTSEC-2026-0403 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- zstd-safe (crates.io): affected from 4.0.0; fixed in 8.2.0\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/RUSTSEC-2026-0403/ (Markdown: https://insights.sbomify.com/RUSTSEC-2026-0403/index.md)","id":"RUSTSEC-2026-0403","markdown":"https://insights.sbomify.com/RUSTSEC-2026-0403/index.md","name":"RUSTSEC-2026-0403","record":{"aliases":[],"analysis":null,"analysis_generated_by":null,"assigner":null,"cpe":[],"cvss":{"score":null,"severity":null,"source":null,"vector":null,"version":null},"cwes":[],"description":"When decompression fails inside a legacy (zstd v0.4 to v0.7) frame, the\nbundled zstd library reports the output buffer as fully written although\nnothing was written. `DCtx::decompress_stream` committed that position even\non error, and for a `Vec\u003cu8\u003e` destination this extended the vector's length\nover uninitialized memory.\n\nLegacy support is enabled by default. A 5- or 6-byte corrupt legacy frame is\nenough: through `zstd::stream::write::Decoder`, up to 32 KiB of stale heap\nmemory is then passed to the wrapped writer on the next `write()` or\n`flush()`, or when an `auto_flush()`/`on_flush()` decoder is dropped. Whether\nthis reaches an attacker depends on where the application sends the\ndecompressed output. `zstd::stream::read::Decoder`, `zstd::decode_all` and\nthe bulk API are not affected.\n\nBefore zstd-safe 4.0.0, output buffers could only be initialized slices.\nThe zstd crate's own writer had the same flaw from 0.4.22 to 0.7.x, which is\ncovered by a separate advisory.\n\nThe flaw was corrected by only committing the buffer positions of a\nsuccessful call.","ecosystems":["crates.io"],"exploits":{"exploitdb":null,"first_seen":null,"github_poc":null,"max_poc_stars":null,"metasploit":null,"nuclei":null,"refs":[],"tier":null},"has_fix":true,"headline":"Uninitialized memory exposed when streaming decompression of a legacy frame fails","id":"RUSTSEC-2026-0403","indexable":true,"kev":null,"kind":"advisory","links":{"ecosystem":"crates.io","product":null,"products":[],"type":null,"year":"2026"},"n_packages":1,"n_references":null,"packages":[{"ecosystem":"crates.io","fixed":["8.2.0"],"introduced":["4.0.0"],"last_affected":[],"package":"zstd-safe","purl":"pkg:cargo/zstd-safe","source":"RUSTSEC-2026-0403"}],"products":null,"published":"2026-10-16","related":[],"sources":[{"class":"open","licence":"CC0 1.0","name":"RustSec","prefix":"RUSTSEC"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":null,"updated":null,"vendors":null},"summary":null,"url":"https://insights.sbomify.com/RUSTSEC-2026-0403/"}