CVE-2020-35861: Bumpalo Out Of Bounds Read Vulnerability

HIGH
Advisory Identifier: GHSA-vqx7-pw4r-29rr
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CVSS 7.5
CWE-125
Published
Advisory Summary

CVE-2020-35861 is a HIGH (CVSS 7.5) out of bounds read vulnerability (CWE-125: Out-of-bounds Read) affecting Bumpalo libraries in the crates.io ecosystem. The issue involves out of bounds read in bumpalo. Remediation is available by upgrading affected packages to version 3.2.1.

CVE-2020-35861 at a Glance

CVE Identifier CVE-2020-35861
GHSA Identifier GHSA-vqx7-pw4r-29rr
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-125: Out-of-bounds Read
Affected Product Bumpalo
Package Ecosystem crates.io
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity None (I:N)
Availability None (A:N)

How to Fix CVE-2020-35861

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

bumpalo fixed: 3.2.1 
Upgrade bumpalo to 3.2.1
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 bumpalo

How to Check if You Are Affected

To determine whether your application is affected by CVE-2020-35861, inspect your project dependencies for Bumpalo:

inspect dependencies for bumpalo

Analyze the terminal output to locate any version of Bumpalo in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.2.1), 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-125: Out-of-bounds Read, where the product reads data past the end, or before the beginning, of the intended buffer. In Bumpalo, 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

An issue was discovered in the bumpalo crate before 3.2.1 for Rust. The realloc feature allows the reading of unknown memory. Attackers can potentially read cryptographic keys.

CVE-2020-35861 Affected Bumpalo Versions

1 component(s)
Fixed Versions:
3.2.1
Product / Package Ecosystem Affected Versions Fixed Version
bumpalo
 crates.io
≥ 3.0.0
< 3.2.1
3.2.1

References

NVD — CVE-2020-35861 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-35861
Bumpalo Source Repository REPOSITORY
https://github.com/fitzgen/bumpalo/issues/69
Bumpalo Source Repository REPOSITORY
https://github.com/fitzgen/bumpalo
rustsec.org/advisories/rustsec-... WEB
https://rustsec.org/advisories/RUSTSEC-2020-0006.html

Frequently Asked Questions

What is CVE-2020-35861?
CVE-2020-35861 is a security vulnerability in Bumpalo involving Out of bounds read in bumpalo under CWE-125: Out-of-bounds Read.
Which Bumpalo versions are affected?
Affected versions include releases prior to 3.2.1 across affected packages: bumpalo.
What version fixes CVE-2020-35861?
Upgrading to 3.2.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is bumpalo affected?
Yes, bumpalo is affected in releases prior to 3.2.1. Upgrade your dependency to 3.2.1 or later.
What is the CVSS score of CVE-2020-35861?
CVE-2020-35861 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.
What CWE is associated with CVE-2020-35861?
CVE-2020-35861 is classified under CWE-125: Out-of-bounds Read (The product reads data past the end, or before the beginning, of the intended buffer.).
How can I check crates.io dependencies for CVE-2020-35861?
Run the dependency tree command: 'inspect dependencies for bumpalo'. 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-vqx7-pw4r-29rr",
  "modified" : "2021-08-19T21:18:29Z",
  "published" : "2021-08-25T20:47:13Z",
  "aliases" : [ "CVE-2020-35861" ],
  "summary" : "Out of bounds read in bumpalo",
  "details" : "An issue was discovered in the bumpalo crate before 3.2.1 for Rust. The realloc feature allows the reading of unknown memory. Attackers can potentially read cryptographic keys.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "bumpalo"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.0.0"
      }, {
        "fixed" : "3.2.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-35861"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/fitzgen/bumpalo/issues/69"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/fitzgen/bumpalo"
  }, {
    "type" : "WEB",
    "url" : "https://rustsec.org/advisories/RUSTSEC-2020-0006.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-125" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-08-19T21:18:29Z",
    "nvd_published_at" : null
  }
}