rust-openssl CVE-2026-41681

Upgrade rust-openssl to version 0.10.78 or later, which contains the fix implemented in commit 826c3888b77add418b394770e2b2e3a72d9f92fe (https://github.com/rust-openssl/rust-openssl/commit/826c3888b77add418b394770e2b2e3a72d9f92fe). Update the dependency in Cargo.toml to openssl = "0.10.78" and run cargo update. Review the patch at https://github.com/rust-openssl/rust-openssl/pull/2608 to understand the fix implementation. If immediate upgrade is not feasible, implement a temporary workaround by manually validating that output buffers passed to MdCtxRef::digest_final() are sized to at least EVP_MD_size() bytes for the hash algorithm in use (16 bytes for MD5, 32 for SHA-256, 64 for SHA-512). This requires calling unsafe OpenSSL FFI functions directly to check digest size before allocation, negating the safety benefits of the Rust wrapper. Alternatively, allocate conservatively large output buffers (64+ bytes) for all digest operations and accept the memory overhead, though this doesn't address the underlying API safety violation. Consult the full advisory at https://github.com/advisories/GHSA-ghm9-cr32-g9qj for additional context.