CVE-2026-124040 (GCVE-0-2026-124040)

Vulnerability from cvelistv5 – Published: 2026-11-06 19:14 – Updated: 2026-11-06 19:14
VLAI
Title
CivetWeb through 1.16 HTTP/2 Use-After-Free via Stale Pseudo-Header State
Summary
CivetWeb through 1.16, when built with USE_HTTP2 and enable_http2 on, contains a use-after-free vulnerability in handle_http2() that retains freed :method and :path pointers. Unauthenticated remote attackers can send a later HEADERS frame omitting these pseudo-headers to influence request method or path seen by access rules, or crash the server.
Severity
9.2 (Critical)
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
8.1 (High)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE
Assigner
VulnCheck CNA
References
Impacted products
Vendor Product Version
civetweb civetweb Affected: 0 , ≤ 1.16 (custom)
    cpe:2.3:a:civetweb_project:civetweb:*:*:*:*:*:*:*:*
Create a notification for this product.
Date Public
2026-03-18 00:00
Credits
PuH4ck3rX Lee Keon-Hyeong
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "civetweb",
          "vendor": "civetweb",
          "versions": [
            {
              "lessThanOrEqual": "1.16",
              "status": "affected",
              "version": "0",
              "versionType": "custom"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:civetweb_project:civetweb:*:*:*:*:*:*:*:*",
                  "versionEndIncluding": "1.16",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "credits": [
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          "type": "finder",
          "value": "PuH4ck3rX"
        },
        {
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          "type": "reporter",
          "value": "Lee Keon-Hyeong"
        }
      ],
      "datePublic": "2026-03-18T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "CivetWeb through 1.16, when built with USE_HTTP2 and enable_http2 on, contains a use-after-free vulnerability in handle_http2() that retains freed :method and :path pointers. Unauthenticated remote attackers can send a later HEADERS frame omitting these pseudo-headers to influence request method or path seen by access rules, or crash the server."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "HIGH",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 9.2,
            "baseSeverity": "CRITICAL",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
            "version": "4.0",
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            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "HIGH"
          },
          "format": "CVSS"
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        {
          "cvssV3_1": {
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            "baseScore": 8.1,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-416",
              "description": "Use After Free",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-11-06T19:14:48.975Z",
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "shortName": "VulnCheck"
      },
      "references": [
        {
          "name": "GitHub Issue #1379",
          "tags": [
            "issue-tracking"
          ],
          "url": "https://github.com/civetweb/civetweb/issues/1379"
        },
        {
          "tags": [
            "product"
          ],
          "url": "https://github.com/civetweb/civetweb"
        },
        {
          "tags": [
            "technical-description"
          ],
          "url": "https://github.com/civetweb/civetweb/blob/v1.16/src/http2.inl#L1574-L1581"
        },
        {
          "name": "VulnCheck Advisory: CivetWeb through 1.16 HTTP/2 Use-After-Free via Stale Pseudo-Header State",
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://www.vulncheck.com/advisories/civetweb-through-1.16-http-2-use-after-free-via-stale-pseudo-header-state"
        }
      ],
      "title": "CivetWeb through 1.16 HTTP/2 Use-After-Free via Stale Pseudo-Header State",
      "x_generator": {
        "engine": "vulncheck-endgame"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
    "cveId": "CVE-2026-124040",
    "datePublished": "2026-11-06T19:14:48.975Z",
    "dateReserved": "2026-11-06T19:11:14.928Z",
    "dateUpdated": "2026-11-06T19:14:48.975Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}



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