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Medium

Global Buffer Overflow in GNU gzip

Type: advisorySources: OSV

GNU gzip contains a global buffer overflow vulnerability in the LZH decompression logic caused by improper reuse of shared global state between different decompression formats within a single execution. GNU gzip maintains a global array that is shared across the LZ77, LZW, and LZH decompression routines and is not reinitialized between files processed in the same invocation. By decompressing a specially crafted LZW file followed by a specially crafted LZH file in a single gzip -d command, an attacker can poison the shared global state and subsequently trigger an out‑of‑bounds read in the LZH decoder. The LZH decompression logic follows stale values left in the shared array, causing reads past the end of the allocated global buffer. This issue has been fixed in commits 63dbf6b3b9e6e781df1a6a64e609b10e23969681 and e7378c2d421be6a286922374425680bbe9ad8b7d.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-41992
Confirmed fixed CVEs
Not specified
Updated in this feed
1 Nov 2026, 17:12 UTC · Revision 1

Source evidence

Global Buffer Overflow in GNU gzip

core-osv · Original source

Published 29 Jun 2026, 10:15 UTC

GNU gzip contains a global buffer overflow vulnerability in the LZH decompression logic caused by improper reuse of shared global state between different decompression formats within a single execution. GNU gzip maintains a global array that is shared across the LZ77, LZW, and LZH decompression routines and is not reinitialized between files processed in the same invocation. By decompressing a specially crafted LZW file followed by a specially crafted LZH file in a single gzip -d command, an attacker can poison the shared global state and subsequently trigger an out‑of‑bounds read in the LZH decoder. The LZH decompression logic follows stale values left in the shared array, causing reads past the end of the allocated global buffer. This issue has been fixed in commits 63dbf6b3b9e6e781df1a6a64e609b10e23969681 and e7378c2d421be6a286922374425680bbe9ad8b7d.

osv:CVE-2026-41992
Complete source record
{
  "id": "c259eb3ab061ed186bcb5ab0e17975f668dcfff2aac71505180e2952b6234d41",
  "url": "https://osv.dev/vulnerability/CVE-2026-41992",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Global Buffer Overflow in GNU gzip",
    "summary": "GNU gzip contains a global buffer overflow vulnerability in the LZH decompression logic caused by improper reuse of shared global state between different decompression formats within a single execution. GNU gzip maintains a global array that is shared across the LZ77, LZW, and LZH decompression routines and is not reinitialized between files processed in the same invocation. By decompressing a specially crafted LZW file followed by a specially crafted LZH file in a single gzip -d command, an attacker can poison the shared global state and subsequently trigger an out‑of‑bounds read in the LZH decoder. The LZH decompression logic follows stale values left in the shared array, causing reads past the end of the allocated global buffer. This issue has been fixed in commits 63dbf6b3b9e6e781df1a6a64e609b10e23969681 and e7378c2d421be6a286922374425680bbe9ad8b7d.",
    "evidence": "osv:CVE-2026-41992",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-41992",
      "aliases": [
        "CVE-2026-41992"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://cgit.git.savannah.gnu.org/cgit/gzip.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "63dbf6b3b9e6e781df1a6a64e609b10e23969681"
                },
                {
                  "fixed": "e7378c2d421be6a286922374425680bbe9ad8b7d"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "63dbf6b3b9e6e781df1a6a64e609b10e23969681"
                      }
                    ],
                    "source": "DESCRIPTION"
                  },
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "63dbf6b3b9e6e781df1a6a64e609b10e23969681"
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                    ],
                    "source": "DESCRIPTION"
                  },
                  {
                    "range": [
                      {
                        "fixed": "63dbf6b3b9e6e781df1a6a64e609b10e23969681"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "e7378c2d421be6a286922374425680bbe9ad8b7d"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-41992.json"
          }
        }
      ],
      "modified": "2026-10-31T10:30:46.279161639Z",
      "provider": "osv",
      "references": [
        "https://cgit.git.savannah.gnu.org/cgit/gzip.git/",
        "https://www.gnu.org/software/gzip/",
        "https://cert.pl/en/posts/2026/04/CVE-2026-41991/",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/41xxx/CVE-2026-41992.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-41992",
        "https://cgit.git.savannah.gnu.org/cgit/gzip.git/commit/?id=63dbf6b3b9e6e781df1a6a64e609b10e23969681",
        "https://cgit.git.savannah.gnu.org/cgit/gzip.git/commit/?id=e7378c2d421be6a286922374425680bbe9ad8b7d"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-126"
        ],
        "cna_assigner": "CERT-PL",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "last_affected": "1.14"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              }
            ]
          },
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "last_affected": "1.14"
                  }
                ],
                "source": "CPE_FIELD",
                "strategy": "CPEApplicability"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/41xxx/CVE-2026-41992.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-41992",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 460065,
  "published_at": "2026-06-29T10:15:57.278+00:00"
}