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Rust OpensslFramework / library · Rust Openssl Project

CVE-2026-41677

CRITICAL · 9.1 CVSS v3.1 Published 2026-04-24
Fix available
A fix is available. Upgrade to 0.10.78 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
rust-openssl provides OpenSSL bindings for the Rust programming language. From 0.9.0 to before 0.10.78, the *_from_pem_callback APIs did not validate the length returned by the user's callback. A password callback that returns a value larger than the buffer it was given can cause some versions of OpenSSL to over-read this buffer. OpenSSL 3.x is not affected by this. This vulnerability is fixed in 0.10.78.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The rust-openssl crate versions 0.9.0 through 0.10.77 contain a buffer over-read vulnerability in the *_from_pem_callback APIs. These functions fail to validate the length returned by user-provided password callbacks; if a callback returns a value larger than the provided buffer, certain OpenSSL versions (prior to 3.x) will over-read past the buffer boundaries, potentially exposing sensitive memory.

MitigationUpgrade rust-openssl to version 0.10.78 or later. Applications using OpenSSL 3.x are not affected.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Rust OpensslFramework / library
Affected:>= 0.9.0, < 0.10.78

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check rust-openssl crate version in your project
    Examine your Cargo.lock file for the rust-openssl crate entry, specifically the version field. Also check your Cargo.toml for the declared version dependency.
    Affected if The rust-openssl version is between 0.9.0 and 0.10.77 inclusive (any version < 0.10.78)
  2. Identify use of *_from_pem_callback APIs
    Search your codebase for calls to any function containing '_from_pem_callback' such as pkey_from_pem_callback, rsa_from_pem_callback, or x509_from_pem_callback.
    Affected if Your code uses any of the *_from_pem_callback functions to parse PEM-encoded keys or certificates with a password callback
  3. Verify OpenSSL version in use
    Check the OpenSSL version linked at runtime by running `openssl version` on your system, or inspect your dependency tree to confirm whether OpenSSL 1.1.x or 2.x is being used versus OpenSSL 3.x.
    Affected if The linked OpenSSL version is 1.x or 2.x (versions prior to 3.0) - OpenSSL 3.x is not affected
  4. Confirm password callback returns variable-length data
    Review your password callback implementation to determine if it returns passwords of varying lengths rather than a fixed maximum-length buffer.
    Affected if The callback can return a length value greater than the buffer size passed to it, triggering the over-read condition

You are affected if you use rust-openssl versions 0.9.0 through 0.10.77, call *_from_pem_callback APIs with a password callback, and link against OpenSSL versions prior to 3.x.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 0.10.78 or later
Fixed in 0.10.78
Interim mitigation

Upgrade rust-openssl to version 0.10.78 or later. Applications using OpenSSL 3.x are not affected.

Recommended fix High confidence

0.10.78 or later

  1. Check the current version of rust-openssl in your Cargo.toml file
  2. Update the rust-openssl version constraint to 0.10.78 or later (e.g., rust-openssl = "0.10.78")
  3. Run `cargo update` to fetch the updated dependency
  4. Run `cargo build` and/or `cargo test` to verify the upgrade compiles and tests pass
Caveat Minimal risk - the fix is a patch release addressing a security vulnerability with no documented breaking changes

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Rust Openssl Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing3.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,210
Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-41677 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data