CVE-2026-55406: Buffa Buffa Has A Use-After-Free Vulnerability

MODERATE
Advisory Identifier: GHSA-9pwq-gcrx-wghh
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CWE-200 CWE-416
Published
Advisory Summary

CVE-2026-55406 is a MODERATE buffa has a use-after-free vulnerability (CWE-200: Exposure of Sensitive Information to an Unauthorized Actor) affecting Buffa libraries in the crates.io ecosystem. The issue involves buffa has a use-after-free in ownedview via unsound 'static lifetime promotion in deref. Remediation is available by upgrading affected packages to version 0.7.0.

CVE-2026-55406 at a Glance

CVE Identifier CVE-2026-55406
GHSA Identifier GHSA-9pwq-gcrx-wghh
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-200: Exposure of Sensitive Information to an Unauthorized Actor
Affected Product Buffa
Package Ecosystem crates.io
Published Date
Last Updated

How to Fix CVE-2026-55406

To remediate this vulnerability, upgrade all affected Buffa dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

buffa fixed: 0.7.0 
Upgrade buffa to 0.7.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for buffa

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-55406, inspect your project dependencies for Buffa:

inspect dependencies for buffa

Analyze the terminal output to locate any version of Buffa in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.7.0), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-200: Exposure of Sensitive Information to an Unauthorized Actor, where the product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. In Buffa, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

A soundness bug in `buffa`'s `OwnedView<V>` allowed safe Rust code to trigger a use-after-free. The `OwnedView::decode` constructor transmuted a borrowed slice to `&'static [u8]`, and the `Deref` implementation exposed the promoted `'static` lifetime on borrowed view fields (such as `&'static str` and `&'static [u8]`) to callers. Because these references appeared to be `'static`, the borrow checker permitted them to outlive the `OwnedView`; once the `OwnedView` was dropped and its backing buffer freed, those references became dangling, enabling memory corruption, information disclosure of freed heap contents, and cross-thread misuse — all without any `unsafe` code in the calling application. Users are advised to update to the latest patched version of buffa. Thank you to hackerone.com/suul for reporting this issue.

CVE-2026-55406 Affected Buffa Versions

1 component(s)
Fixed Versions:
0.7.0
Product / Package Ecosystem Affected Versions Fixed Version
buffa
 crates.io
< 0.7.0
0.7.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/anthropics/buffa/security/advisories/GHSA-9pwq-gcrx-wghh
NVD — CVE-2026-55406 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-55406
Buffa Source Repository REPOSITORY
https://github.com/anthropics/buffa/pull/154
Security Fix Commit FIX COMMIT
https://github.com/anthropics/buffa/commit/7dcf50a1a40eca6ed8d6c6dd59f4310aa0d68b0e
Buffa Source Repository REPOSITORY
https://github.com/anthropics/buffa
Buffa Release RELEASE
https://github.com/anthropics/buffa/releases/tag/v0.7.0

Frequently Asked Questions

What is CVE-2026-55406?
CVE-2026-55406 is a security vulnerability in Buffa involving Buffa has a Use-After-Free in OwnedView via Unsound 'static Lifetime Promotion in Deref under CWE-200: Exposure of Sensitive Information to an Unauthorized Actor.
Which Buffa versions are affected?
Affected versions include releases prior to 0.7.0 across affected packages: buffa.
What version fixes CVE-2026-55406?
Upgrading to 0.7.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is buffa affected?
Yes, buffa is affected in releases prior to 0.7.0. Upgrade your dependency to 0.7.0 or later.
What CWE is associated with CVE-2026-55406?
CVE-2026-55406 is classified under CWE-200: Exposure of Sensitive Information to an Unauthorized Actor (The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.).
How can I check crates.io dependencies for CVE-2026-55406?
Run the dependency tree command: 'inspect dependencies for buffa'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-9pwq-gcrx-wghh",
  "modified" : "2026-08-28T18:33:58Z",
  "published" : "2026-08-28T18:33:58Z",
  "aliases" : [ "CVE-2026-55406" ],
  "summary" : "Buffa has a Use-After-Free in OwnedView via Unsound 'static Lifetime Promotion in Deref",
  "details" : "A soundness bug in `buffa`'s `OwnedView<V>` allowed safe Rust code to trigger a use-after-free. The `OwnedView::decode` constructor transmuted a borrowed slice to `&'static [u8]`, and the `Deref` implementation exposed the promoted `'static` lifetime on borrowed view fields (such as `&'static str` and `&'static [u8]`) to callers. Because these references appeared to be `'static`, the borrow checker permitted them to outlive the `OwnedView`; once the `OwnedView` was dropped and its backing buffer freed, those references became dangling, enabling memory corruption, information disclosure of freed heap contents, and cross-thread misuse — all without any `unsafe` code in the calling application. Users are advised to update to the latest patched version of buffa.\n\nThank you to hackerone.com/suul for reporting this issue.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "buffa"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.7.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/anthropics/buffa/security/advisories/GHSA-9pwq-gcrx-wghh"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-55406"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/anthropics/buffa/pull/154"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/anthropics/buffa/commit/7dcf50a1a40eca6ed8d6c6dd59f4310aa0d68b0e"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/anthropics/buffa"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/anthropics/buffa/releases/tag/v0.7.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-200", "CWE-416" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-08-28T18:33:58Z",
    "nvd_published_at" : "2026-07-16T17:16:57Z"
  }
}