Vulnerability-Lookup

GHSA-9PWQ-GCRX-WGHH

Vulnerability from github – Published: 2026-08-28 18:33 – Updated: 2026-08-28 18:33

Summary

Buffa has a Use-After-Free in OwnedView via Unsound 'static Lifetime Promotion in Deref

Details

A soundness bug in buffa's OwnedView<V> allowed safe Rust code to trigger a use-after-free. The OwnedView::decode constructor transmuted a borrowed slice to &'static [u8], and the Deref implementation exposed the promoted 'static lifetime on borrowed view fields (such as &'static str and &'static [u8]) to callers. Because these references appeared to be 'static, the borrow checker permitted them to outlive the OwnedView; once the OwnedView was dropped and its backing buffer freed, those references became dangling, enabling memory corruption, information disclosure of freed heap contents, and cross-thread misuse — all without any unsafe code in the calling application. Users are advised to update to the latest patched version of buffa.

Thank you to hackerone.com/suul for reporting this issue.

Severity

5.9 (Medium)


                  
                    CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N

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{
  "affected": [
    {
      "package": {
        "ecosystem": "crates.io",
        "name": "buffa"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.7.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-55406"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-200",
      "CWE-416"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-28T18:33:58Z",
    "nvd_published_at": "2026-07-16T17:16:57Z",
    "severity": "MODERATE"
  },
  "details": "A soundness bug in `buffa`\u0027s `OwnedView\u003cV\u003e` allowed safe Rust code to trigger a use-after-free. The `OwnedView::decode` constructor transmuted a borrowed slice to `\u0026\u0027static [u8]`, and the `Deref` implementation exposed the promoted `\u0027static` lifetime on borrowed view fields (such as `\u0026\u0027static str` and `\u0026\u0027static [u8]`) to callers. Because these references appeared to be `\u0027static`, the borrow checker permitted them to outlive the `OwnedView`; once the `OwnedView` was dropped and its backing buffer freed, those references became dangling, enabling memory corruption, information disclosure of freed heap contents, and cross-thread misuse \u2014 all without any `unsafe` code in the calling application. Users are advised to update to the latest patched version of buffa.\n\nThank you to hackerone.com/suul for reporting this issue.",
  "id": "GHSA-9pwq-gcrx-wghh",
  "modified": "2026-08-28T18:33:58Z",
  "published": "2026-08-28T18:33:58Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/anthropics/buffa/security/advisories/GHSA-9pwq-gcrx-wghh"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-55406"
    },
    {
      "type": "WEB",
      "url": "https://github.com/anthropics/buffa/pull/154"
    },
    {
      "type": "WEB",
      "url": "https://github.com/anthropics/buffa/commit/7dcf50a1a40eca6ed8d6c6dd59f4310aa0d68b0e"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/anthropics/buffa"
    },
    {
      "type": "WEB",
      "url": "https://github.com/anthropics/buffa/releases/tag/v0.7.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Buffa has a Use-After-Free in OwnedView via Unsound \u0027static Lifetime Promotion in Deref"
}

CVE-2026-55406 (GCVE-0-2026-55406)

Vulnerability from cvelistv5 – Published: 2026-07-16 15:54 – Updated: 2026-07-16 16:47

Title

Buffa: Use-After-Free in OwnedView via Unsound 'static Lifetime Promotion in Deref

Summary

Buffa is a pure-Rust Protocol Buffers implementation with first-class protobuf editions support. Prior to 0.7.0, a soundness bug in the OwnedView<V> type allowed safe Rust code to trigger a use-after-free: the OwnedView::decode constructor transmuted a borrowed slice to &'static [u8], and the Deref implementation exposed the promoted 'static lifetime on borrowed view fields (such as &'static str and &'static [u8]) to callers, so the borrow checker permitted those references to outlive the OwnedView; once the OwnedView was dropped and its backing buffer freed, the references became dangling, enabling memory corruption, information disclosure of freed heap contents, and cross-thread misuse without any unsafe code in the calling application. This issue is fixed in version 0.7.0.

Severity

5.9 (Medium)


                        
                          CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-16 16:47 UTC

CWE

CWE-200 - Exposure of Sensitive Information to an Unauthorized Actor
CWE-416 - Use After Free

Assigner

GitHub_M CNA under the mitre root

CNA scorecard C 72/100 over 7674 records in the last 180 days details

References

4 references

URL	Tags
https://github.com/anthropics/buffa/security/advi…	x_refsource_CONFIRM
https://github.com/anthropics/buffa/pull/154	x_refsource_MISC
https://github.com/anthropics/buffa/commit/7dcf50…	x_refsource_MISC
https://github.com/anthropics/buffa/releases/tag/v0.7.0	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
anthropics	buffa	Affected: < 0.7.0

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-55406",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-16T16:47:16.390744Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-16T16:47:37.717Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "buffa",
          "vendor": "anthropics",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.7.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Buffa is a pure-Rust Protocol Buffers implementation with first-class protobuf editions support. Prior to 0.7.0, a soundness bug in the OwnedView\u003cV\u003e type allowed safe Rust code to trigger a use-after-free: the OwnedView::decode constructor transmuted a borrowed slice to \u0026\u0027static [u8], and the Deref implementation exposed the promoted \u0027static lifetime on borrowed view fields (such as \u0026\u0027static str and \u0026\u0027static [u8]) to callers, so the borrow checker permitted those references to outlive the OwnedView; once the OwnedView was dropped and its backing buffer freed, the references became dangling, enabling memory corruption, information disclosure of freed heap contents, and cross-thread misuse without any unsafe code in the calling application. This issue is fixed in version 0.7.0."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "HIGH",
            "attackRequirements": "PRESENT",
            "attackVector": "LOCAL",
            "baseScore": 5.9,
            "baseSeverity": "MEDIUM",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "LOW"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-200",
              "description": "CWE-200: Exposure of Sensitive Information to an Unauthorized Actor",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-416",
              "description": "CWE-416: Use After Free",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-16T15:54:29.511Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/anthropics/buffa/security/advisories/GHSA-9pwq-gcrx-wghh",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/anthropics/buffa/security/advisories/GHSA-9pwq-gcrx-wghh"
        },
        {
          "name": "https://github.com/anthropics/buffa/pull/154",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/anthropics/buffa/pull/154"
        },
        {
          "name": "https://github.com/anthropics/buffa/commit/7dcf50a1a40eca6ed8d6c6dd59f4310aa0d68b0e",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/anthropics/buffa/commit/7dcf50a1a40eca6ed8d6c6dd59f4310aa0d68b0e"
        },
        {
          "name": "https://github.com/anthropics/buffa/releases/tag/v0.7.0",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/anthropics/buffa/releases/tag/v0.7.0"
        }
      ],
      "source": {
        "advisory": "GHSA-9pwq-gcrx-wghh",
        "discovery": "UNKNOWN"
      },
      "title": "Buffa: Use-After-Free in OwnedView via Unsound \u0027static Lifetime Promotion in Deref"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-55406",
    "datePublished": "2026-07-16T15:54:29.511Z",
    "dateReserved": "2026-06-16T21:48:43.124Z",
    "dateUpdated": "2026-07-16T16:47:37.717Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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