RUSTSEC-2026-0348

    Dashboard / Vulnerabilities / RUSTSEC-2026-0348

    RUSTSEC-2026-0348

    Published: 14 Oct 2026Last Modified: 9 Nov 2026

    Summary: Brotli certificate decompression can allocate up to 1 GiB before authentication

    Details: The built-in Brotli certificate decompressor (enabled by the non-default `brotli` crate feature) bounded the size of the decompressed output, but accepted a peer-selected history window. Brotli's large-window extension was enabled, so a five-byte header could cause an allocation of 1 GiB. A peer can abort a process whose allocator cannot satisfy that request. No trusted certificate is required by the attacker. Affected configurations are: - clients that enable the `brotli` feature and connect to a malicious server, and - servers that enable the `brotli` feature and request client certificates. Applications that do not enable the `brotli` feature are not affected.

    References: https://crates.io/crates/rustls, https://rustsec.org/advisories/RUSTSEC-2026-0348.html, https://github.com/rustls/rustls/pull/3297

    Affected packages

    Package

    Name: rustls

    Purl: pkg:cargo/rustls

    Affected ranges

    Type: SEMVER

    Events:

    Introduced- 0.23.9
    Fixed -0.23.46

    Affected versions

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High