CVE-2026-11941 (GCVE-0-2026-11941)

Vulnerability from cvelistv5 – Published: 2026-06-19 09:55 – Updated: 2026-06-19 09:55
VLAI
Title
Use-after-free in connection ID iterator and FFI functions
Summary
Cloudflare Quiche was affected by 2 use-after-free vulnerabilities in the connection ID iterator FFI functions. The “quiche_connection_id_iter_next” and “quiche_conn_retired_scid_next” functions would return a pointer to a “ConnectionId” to the applications via function arguments, but the owned “ConnectionId” would be dropped at the end of those functions' scope. Only applications using those FFI functions are affected. The FFI API is disabled by default by a build-time feature flag. Impact If unpatched, an application calling the affected FFI functions will dereference freed memory. The most likely outcome is undefined behavior leading to a process crash (denial of service). Depending on allocator state, the read may also return adjacent heap contents, resulting in limited information disclosure or incorrect connection identifier handling. Mitigation Users are requested to upgrade to quiche 0.29.2 which is the earliest version containing the fix for this issue.
CWE
Assigner
Impacted products
Vendor Product Version
Cloudflare Quiche Affected: 0.20.0 , ≤ 0.29.1 (semver)
Create a notification for this product.
Date Public
2026-06-19 09:49
Show details on NVD website

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          "product": "Quiche",
          "repo": "https://github.com/cloudflare/quiche",
          "vendor": "Cloudflare",
          "versions": [
            {
              "lessThanOrEqual": "0.29.1",
              "status": "affected",
              "version": "0.20.0",
              "versionType": "semver"
            }
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        }
      ],
      "datePublic": "2026-06-19T09:49:00.000Z",
      "descriptions": [
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              "value": "\u003cp\u003eCloudflare Quiche was affected by 2 use-after-free vulnerabilities in the connection ID iterator FFI functions.\u003c/p\u003e\u003cp\u003eThe \u201cquiche_connection_id_iter_next\u201d and \u201cquiche_conn_retired_scid_next\u201d functions would return a pointer to a \u201cConnectionId\u201d to the applications via function arguments, but the owned \u201cConnectionId\u201d would be dropped at the end of those functions\u0027 scope.\u003c/p\u003e\u003cp\u003eOnly applications using those FFI functions are affected. The FFI API is disabled by default by a build-time feature flag.\u003c/p\u003e\u003cp\u003e\u003cspan\u003e\u003cb\u003eImpact\u003cbr\u003e\u003c/b\u003e\u003c/span\u003e\u003cspan\u003eIf unpatched, an application calling the affected FFI functions will dereference freed memory. The most likely outcome is undefined behavior leading to a process crash (denial of service). Depending on allocator state, the read may also return adjacent heap contents, resulting in limited information disclosure or incorrect connection identifier handling.\u003c/span\u003e\u003c/p\u003e\u003cp\u003e\u003cspan\u003e\u003cb\u003eMitigation\u003cbr\u003e\u003c/b\u003e\u003c/span\u003e\u003cspan\u003eUsers are requested to upgrade to quiche 0.29.2 which is the earliest version containing the fix for this issue.\u003c/span\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e\u003c/b\u003e\u003cbr\u003e\u003c/p\u003e\u003cbr\u003e"
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        }
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            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "LOW",
            "baseScore": 5.6,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
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        "dateUpdated": "2026-06-19T09:55:54.501Z",
        "orgId": "a22f1246-ba21-4bb4-a601-ad51614c1513",
        "shortName": "cloudflare"
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      "references": [
        {
          "url": "https://github.com/cloudflare/quiche/security/advisories/GHSA-mh64-ph39-mrc9"
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        "discovery": "UNKNOWN"
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    "datePublished": "2026-06-19T09:55:54.501Z",
    "dateReserved": "2026-06-10T20:16:34.590Z",
    "dateUpdated": "2026-06-19T09:55:54.501Z",
    "state": "PUBLISHED"
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}


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