CVE-2026-16615 (GCVE-0-2026-16615)

Vulnerability from cvelistv5 – Published: 2026-07-22 16:12 – Updated: 2026-07-23 16:36
VLAI
Title
Librest: weak random number generation in pkce implementation
Summary
A flaw was found in librest. The PKCE implementation for OAuth authorization uses the GRand function from the GLib API, a cryptographically insecure pseudo-random number generator. Because the generated "code verifier" lacks sufficient cryptographic entropy, a malicious actor can reverse-engineer the pseudo-random number generator (PRNG) seed to predict or reconstruct the code verifier string, allowing an attacker to bypass PKCE protections and successfully impersonate the client during the OAuth 2.0 authorization flow.
Severity
6.8 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
SSVC
Exploitation: none Automatable: no Technical Impact: total
CISA Coordinator (v2.0.3)
CWE
  • CWE-338 - Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
Assigner
References
Impacted products
Vendor Product Version
GNOME librest Affected: 0 , < * (semver)
Create a notification for this product.
Red Hat Red Hat Enterprise Linux 10     cpe:/o:redhat:enterprise_linux:10
 Create a notification for this product.
Date Public
2026-06-08 00:00
Credits
Red Hat would like to thank Cole Blakley for reporting this issue.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-16615",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-22T16:43:25.862726Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-22T16:43:38.173Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://gitlab.gnome.org/GNOME/librest",
          "defaultStatus": "unaffected",
          "packageName": "librest",
          "product": "librest",
          "vendor": "GNOME",
          "versions": [
            {
              "lessThan": "*",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:10"
          ],
          "defaultStatus": "affected",
          "packageName": "rest",
          "product": "Red Hat Enterprise Linux 10",
          "vendor": "Red Hat"
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "Red Hat would like to thank Cole Blakley for reporting this issue."
        }
      ],
      "datePublic": "2026-06-08T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "A flaw was found in librest. The PKCE implementation for OAuth authorization uses the GRand function from the GLib API, a cryptographically insecure pseudo-random number generator. Because the generated \"code verifier\" lacks sufficient cryptographic entropy, a malicious actor can reverse-engineer the pseudo-random number generator (PRNG) seed to predict or reconstruct the code verifier string, allowing an attacker to bypass PKCE protections and successfully impersonate the client during the OAuth 2.0 authorization flow."
        }
      ],
      "metrics": [
        {
          "other": {
            "content": {
              "namespace": "https://access.redhat.com/security/updates/classification/",
              "value": "Important"
            },
            "type": "Red Hat severity rating"
          }
        },
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 6.8,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N",
            "version": "3.1"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-338",
              "description": "Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-23T16:36:44.028Z",
        "orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
        "shortName": "redhat"
      },
      "references": [
        {
          "tags": [
            "vdb-entry",
            "x_refsource_REDHAT"
          ],
          "url": "https://access.redhat.com/security/cve/CVE-2026-16615"
        },
        {
          "name": "RHBZ#2504432",
          "tags": [
            "issue-tracking",
            "x_refsource_REDHAT"
          ],
          "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2504432"
        },
        {
          "url": "https://gitlab.gnome.org/GNOME/librest/-/issues/25"
        }
      ],
      "timeline": [
        {
          "lang": "en",
          "time": "2026-06-08T00:00:00.000Z",
          "value": "Reported to Red Hat."
        },
        {
          "lang": "en",
          "time": "2026-06-08T00:00:00.000Z",
          "value": "Made public."
        }
      ],
      "title": "Librest: weak random number generation in pkce implementation",
      "workarounds": [
        {
          "lang": "en",
          "value": "Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update the affected package as soon as possible."
        }
      ],
      "x_generator": {
        "engine": "cvelib 1.8.0"
      },
      "x_redhatCweChain": "CWE-338: Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
    "assignerShortName": "redhat",
    "cveId": "CVE-2026-16615",
    "datePublished": "2026-07-22T16:12:03.536Z",
    "dateReserved": "2026-07-22T14:38:37.901Z",
    "dateUpdated": "2026-07-23T16:36:44.028Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-16615",
      "date": "2026-07-24",
      "epss": "0.00252",
      "percentile": "0.16708"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-16615\",\"sourceIdentifier\":\"secalert@redhat.com\",\"published\":\"2026-07-22T17:16:55.863\",\"lastModified\":\"2026-07-23T17:16:26.947\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"A flaw was found in librest. The PKCE implementation for OAuth authorization uses the GRand function from the GLib API, a cryptographically insecure pseudo-random number generator. Because the generated \\\"code verifier\\\" lacks sufficient cryptographic entropy, a malicious actor can reverse-engineer the pseudo-random number generator (PRNG) seed to predict or reconstruct the code verifier string, allowing an attacker to bypass PKCE protections and successfully impersonate the client during the OAuth 2.0 authorization flow.\"}],\"affected\":[{\"source\":\"secalert@redhat.com\",\"affectedData\":[{\"vendor\":\"GNOME\",\"product\":\"librest\",\"defaultStatus\":\"unaffected\",\"collectionURL\":\"https://gitlab.gnome.org/GNOME/librest\",\"packageName\":\"librest\",\"versions\":[{\"version\":\"0\",\"lessThan\":\"*\",\"versionType\":\"semver\",\"status\":\"affected\"}]},{\"vendor\":\"Red Hat\",\"product\":\"Red Hat Enterprise Linux 10\",\"defaultStatus\":\"affected\",\"collectionURL\":\"https://access.redhat.com/downloads/content/package-browser/\",\"packageName\":\"rest\",\"cpes\":[\"cpe:/o:redhat:enterprise_linux:10\"]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"secalert@redhat.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N\",\"baseScore\":6.8,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"REQUIRED\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":1.6,\"impactScore\":5.2}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2026-07-22T16:43:25.862726Z\",\"id\":\"CVE-2026-16615\",\"options\":[{\"exploitation\":\"none\"},{\"automatable\":\"no\"},{\"technicalImpact\":\"total\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"secalert@redhat.com\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-338\"}]}],\"references\":[{\"url\":\"https://access.redhat.com/security/cve/CVE-2026-16615\",\"source\":\"secalert@redhat.com\"},{\"url\":\"https://bugzilla.redhat.com/show_bug.cgi?id=2504432\",\"source\":\"secalert@redhat.com\"},{\"url\":\"https://gitlab.gnome.org/GNOME/librest/-/issues/25\",\"source\":\"secalert@redhat.com\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Important",
      "current_release_date": "2026-07-23T16:36:39+00:00",
      "cve": "CVE-2026-16615",
      "id": "CVE-2026-16615",
      "initial_release_date": "2026-06-08T00:00:00+00:00",
      "product_status:known_affected": "2",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "librest: weak random number generation in PKCE implementation",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-16615.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-16615\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"total\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-07-22T16:43:25.862726Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-07-22T16:43:31.917Z\"}}], \"cna\": {\"title\": \"Librest: weak random number generation in pkce implementation\", \"credits\": [{\"lang\": \"en\", \"value\": \"Red Hat would like to thank Cole Blakley for reporting this issue.\"}], \"metrics\": [{\"other\": {\"type\": \"Red Hat severity rating\", \"content\": {\"value\": \"Important\", \"namespace\": \"https://access.redhat.com/security/updates/classification/\"}}}, {\"format\": \"CVSS\", \"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 6.8, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"MEDIUM\", \"vectorString\": \"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N\", \"integrityImpact\": \"HIGH\", \"userInteraction\": \"REQUIRED\", \"attackComplexity\": \"HIGH\", \"availabilityImpact\": \"NONE\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"HIGH\"}}], \"affected\": [{\"vendor\": \"GNOME\", \"product\": \"librest\", \"versions\": [{\"status\": \"affected\", \"version\": \"0\", \"lessThan\": \"*\", \"versionType\": \"semver\"}], \"packageName\": \"librest\", \"collectionURL\": \"https://gitlab.gnome.org/GNOME/librest\", \"defaultStatus\": \"unaffected\"}, {\"cpes\": [\"cpe:/o:redhat:enterprise_linux:10\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat Enterprise Linux 10\", \"packageName\": \"rest\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"defaultStatus\": \"affected\"}], \"timeline\": [{\"lang\": \"en\", \"time\": \"2026-06-08T00:00:00.000Z\", \"value\": \"Reported to Red Hat.\"}, {\"lang\": \"en\", \"time\": \"2026-06-08T00:00:00.000Z\", \"value\": \"Made public.\"}], \"datePublic\": \"2026-06-08T00:00:00.000Z\", \"references\": [{\"url\": \"https://access.redhat.com/security/cve/CVE-2026-16615\", \"tags\": [\"vdb-entry\", \"x_refsource_REDHAT\"]}, {\"url\": \"https://bugzilla.redhat.com/show_bug.cgi?id=2504432\", \"name\": \"RHBZ#2504432\", \"tags\": [\"issue-tracking\", \"x_refsource_REDHAT\"]}, {\"url\": \"https://gitlab.gnome.org/GNOME/librest/-/issues/25\"}], \"workarounds\": [{\"lang\": \"en\", \"value\": \"Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update the affected package as soon as possible.\"}], \"x_generator\": {\"engine\": \"cvelib 1.8.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"A flaw was found in librest. The PKCE implementation for OAuth authorization uses the GRand function from the GLib API, a cryptographically insecure pseudo-random number generator. Because the generated \\\"code verifier\\\" lacks sufficient cryptographic entropy, a malicious actor can reverse-engineer the pseudo-random number generator (PRNG) seed to predict or reconstruct the code verifier string, allowing an attacker to bypass PKCE protections and successfully impersonate the client during the OAuth 2.0 authorization flow.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-338\", \"description\": \"Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)\"}]}], \"providerMetadata\": {\"orgId\": \"53f830b8-0a3f-465b-8143-3b8a9948e749\", \"shortName\": \"redhat\", \"dateUpdated\": \"2026-07-23T16:36:44.028Z\"}, \"x_redhatCweChain\": \"CWE-338: Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)\"}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-16615\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-07-23T16:36:44.028Z\", \"dateReserved\": \"2026-07-22T14:38:37.901Z\", \"assignerOrgId\": \"53f830b8-0a3f-465b-8143-3b8a9948e749\", \"datePublished\": \"2026-07-22T16:12:03.536Z\", \"assignerShortName\": \"redhat\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.