CVE-2026-55406
Deferred Deferred - Pending Action

Use-After-Free in Buffa Rust Protocol Buffers Library

Publication date: 2026-07-16

Last updated on: 2026-07-16

Assigner: GitHub, Inc.

Description
Buffa is a pure-Rust Protocol Buffers implementation with first-class protobuf editions support. Prior to 0.7.0, a soundness bug in the OwnedView<V> type 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, so the borrow checker permitted those references to outlive the OwnedView; once the OwnedView was dropped and its backing buffer freed, the references became dangling, enabling memory corruption, information disclosure of freed heap contents, and cross-thread misuse without any unsafe code in the calling application. This issue is fixed in version 0.7.0.

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Meta Information

Published
2026-07-16
Last Modified
2026-07-16
Generated
2026-07-16
AI Q&A
2026-07-16
EPSS Evaluated
N/A
NVD
CVE-2026-55406
EUVD
EUVD-2026-44949

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
anthropics buffa to 0.7.0 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-416 The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
CWE-200 The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.

Attack-Flow Graph

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Executive Summary

This vulnerability is a use-after-free bug in the Buffa Rust library before version 0.7.0. It involves the OwnedView type incorrectly exposing a 'static lifetime on borrowed data, allowing safe Rust code to create dangling references. These references could outlive the OwnedView instance, leading to memory corruption or information disclosure when the underlying buffer is freed.

Detection Guidance

This vulnerability is specific to the Buffa Rust library and requires code inspection rather than network or system commands. Check if your project uses Buffa versions prior to 0.7.0. Review code for OwnedView::decode usage and ensure no borrowed slices are transmuted to 'static lifetimes.

Impact Analysis

This vulnerability could allow attackers to corrupt memory, disclose sensitive data from freed heap memory, or misuse references across threads. Since it involves safe Rust code, applications using affected versions might experience crashes, data leaks, or unexpected behavior without any unsafe code in the application itself.

Compliance Impact

This vulnerability could potentially lead to information disclosure of freed heap contents, which may violate data protection requirements under GDPR (e.g., Article 32 on security of processing) and HIPAA (e.g., safeguards for protected health information). The use-after-free scenario might expose sensitive data in memory, risking unauthorized access or corruption of personal or health data.

Mitigation Strategies

Upgrade Buffa to version 0.7.0 or later. Remove or replace any code using OwnedView::decode with transmuted 'static lifetimes. Audit dependencies for similar patterns in other libraries.

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