CVE-2020-35918: Branca Unexpected Panic When Decoding Tokens Vulnerability

MODERATE
Advisory Identifier: GHSA-c9rv-3jmq-527w
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CVSS 5.5
CWE-20
Published
Advisory Summary

CVE-2020-35918 is a MODERATE (CVSS 5.5) unexpected panic when decoding tokens vulnerability (CWE-20: Improper Input Validation) affecting Branca libraries in the crates.io ecosystem. The issue involves unexpected panic when decoding tokens in branca. Remediation is available by upgrading affected packages to version 0.10.0.

CVE-2020-35918 at a Glance

CVE Identifier CVE-2020-35918
GHSA Identifier GHSA-c9rv-3jmq-527w
Severity MODERATE
CVSS v3.1 Base Score 5.5
CWE Classification CWE-20: Improper Input Validation
Affected Product Branca
Package Ecosystem crates.io
Published Date
Last Updated

Security Impact

CVSS: 5.5

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

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

How to Fix CVE-2020-35918

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

branca fixed: 0.10.0 
Upgrade branca to 0.10.0
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 branca

How to Check if You Are Affected

To determine whether your application is affected by CVE-2020-35918, inspect your project dependencies for Branca:

inspect dependencies for branca

Analyze the terminal output to locate any version of Branca in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.10.0), 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-20: Improper Input Validation, where the product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. In Branca, 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

Prior to 0.10.0 it was possible to have both decoding functions panic unexpectedly, by supplying tokens with an incorrect base62 encoding. The documentation stated that an error should have been reported instead.

CVE-2020-35918 Affected Branca Versions

1 component(s)
Fixed Versions:
0.10.0
Product / Package Ecosystem Affected Versions Fixed Version
branca
 crates.io
< 0.10.0
0.10.0

References

NVD — CVE-2020-35918 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-35918
Branca Source Repository REPOSITORY
https://github.com/return/branca/issues/24
Branca Source Repository REPOSITORY
https://github.com/tuupola/branca-spec/issues/22
Security Fix Commit FIX COMMIT
https://github.com/return/branca/commit/7da3274bd99b05dce9c3f9b4b129d0145c71820b
Branca Source Repository REPOSITORY
https://github.com/return/branca
rustsec.org/advisories/rustsec-... WEB
https://rustsec.org/advisories/RUSTSEC-2020-0075.html

Frequently Asked Questions

What is CVE-2020-35918?
CVE-2020-35918 is a security vulnerability in Branca involving Unexpected panic when decoding tokens in branca under CWE-20: Improper Input Validation.
Which Branca versions are affected?
Affected versions include releases prior to 0.10.0 across affected packages: branca.
What version fixes CVE-2020-35918?
Upgrading to 0.10.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is branca affected?
Yes, branca is affected in releases prior to 0.10.0. Upgrade your dependency to 0.10.0 or later.
What is the CVSS score of CVE-2020-35918?
CVE-2020-35918 has a CVSS v3.1 base score of 5.5 (MODERATE) with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2020-35918?
CVE-2020-35918 is classified under CWE-20: Improper Input Validation (The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.).
How can I check crates.io dependencies for CVE-2020-35918?
Run the dependency tree command: 'inspect dependencies for branca'. 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-c9rv-3jmq-527w",
  "modified" : "2023-06-13T17:09:32Z",
  "published" : "2021-08-25T20:49:50Z",
  "aliases" : [ "CVE-2020-35918" ],
  "summary" : "Unexpected panic when decoding tokens in branca",
  "details" : "Prior to 0.10.0 it was possible to have both decoding functions panic unexpectedly, by supplying tokens with an incorrect base62 encoding.\nThe documentation stated that an error should have been reported instead.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "branca"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.10.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-35918"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/return/branca/issues/24"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/tuupola/branca-spec/issues/22"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/return/branca/commit/7da3274bd99b05dce9c3f9b4b129d0145c71820b"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/return/branca"
  }, {
    "type" : "WEB",
    "url" : "https://rustsec.org/advisories/RUSTSEC-2020-0075.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-20" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-08-19T20:50:27Z",
    "nvd_published_at" : "2020-12-31T09:15:00Z"
  }
}