CVE-2026-41681: rust-openssl RustMdCtxRef::digest_final() Writes Past Caller Buffer Vulnerability

HIGH
Advisory Identifier: GHSA-ghm9-cr32-g9qj
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CWE-121
Published
Advisory Summary

CVE-2026-41681 is a HIGH rustmdctxref::digest_final() writes past caller buffer vulnerability (CWE-121: Stack-based Buffer Overflow) affecting rust-openssl libraries in the crates.io ecosystem. The issue involves rustmdctxref::digest_final() writes past caller buffer with no length check. Remediation is available by upgrading affected packages to version 0.10.78.

CVE-2026-41681 at a Glance

CVE Identifier CVE-2026-41681
GHSA Identifier GHSA-ghm9-cr32-g9qj
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-121: Stack-based Buffer Overflow
Affected Product rust-openssl
Package Ecosystem crates.io
Published Date
Last Updated

How to Fix CVE-2026-41681

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

openssl fixed: 0.10.78 
Upgrade openssl to 0.10.78
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 openssl

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-41681, inspect your project dependencies for rust-openssl:

inspect dependencies for openssl

Analyze the terminal output to locate any version of rust-openssl in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.10.78), 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-121: Stack-based Buffer Overflow, where a stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). In rust-openssl, 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

`EVP_DigestFinal()` always writes `EVP_MD_CTX_size(ctx)` to the `out` buffer. If `out` is smaller than that, `MdCtxRef::digest_final()` writes past its end, usually corrupting the stack. This is reachable from safe Rust.

CVE-2026-41681 Affected rust-openssl Versions

1 component(s)
Fixed Versions:
0.10.78
Product / Package Ecosystem Affected Versions Fixed Version
openssl
 crates.io
≥ 0.10.39
< 0.10.78
0.10.78

References

GitHub Advisory / Wiki ADVISORY
https://github.com/rust-openssl/rust-openssl/security/advisories/GHSA-ghm9-cr32-g9qj
NVD — CVE-2026-41681 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-41681
rust-openssl Source Repository REPOSITORY
https://github.com/rust-openssl/rust-openssl/pull/2608
Security Fix Commit FIX COMMIT
https://github.com/rust-openssl/rust-openssl/commit/826c3888b77add418b394770e2b2e3a72d9f92fe
rust-openssl Source Repository REPOSITORY
https://github.com/rust-openssl/rust-openssl
rust-openssl Release RELEASE
https://github.com/rust-openssl/rust-openssl/releases/tag/openssl-v0.10.78

Frequently Asked Questions

What is CVE-2026-41681?
CVE-2026-41681 is a security vulnerability in rust-openssl involving rustMdCtxRef::digest_final() writes past caller buffer with no length check under CWE-121: Stack-based Buffer Overflow.
Which rust-openssl versions are affected?
Affected versions include releases prior to 0.10.78 across affected packages: openssl.
What version fixes CVE-2026-41681?
Upgrading to 0.10.78 (or the latest patched release for your respective branch) resolves the vulnerability.
Is openssl affected?
Yes, openssl is affected in releases prior to 0.10.78. Upgrade your dependency to 0.10.78 or later.
What CWE is associated with CVE-2026-41681?
CVE-2026-41681 is classified under CWE-121: Stack-based Buffer Overflow (A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).).
How can I check crates.io dependencies for CVE-2026-41681?
Run the dependency tree command: 'inspect dependencies for openssl'. 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-ghm9-cr32-g9qj",
  "modified" : "2026-04-27T16:41:47Z",
  "published" : "2026-04-22T21:05:02Z",
  "aliases" : [ "CVE-2026-41681" ],
  "summary" : "rust-openssl: rustMdCtxRef::digest_final() writes past caller buffer with no length check",
  "details" : "`EVP_DigestFinal()` always writes `EVP_MD_CTX_size(ctx)` to the `out` buffer. If `out` is smaller than that, `MdCtxRef::digest_final()` writes past its end, usually corrupting the stack. This is reachable from safe Rust.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "openssl"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.10.39"
      }, {
        "fixed" : "0.10.78"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/rust-openssl/rust-openssl/security/advisories/GHSA-ghm9-cr32-g9qj"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-41681"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/rust-openssl/rust-openssl/pull/2608"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/rust-openssl/rust-openssl/commit/826c3888b77add418b394770e2b2e3a72d9f92fe"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/rust-openssl/rust-openssl"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/rust-openssl/rust-openssl/releases/tag/openssl-v0.10.78"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-121" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-22T21:05:02Z",
    "nvd_published_at" : "2026-04-24T18:16:29Z"
  }
}