CVE-2026-6477 (GCVE-0-2026-6477)
Vulnerability from cvelistv5
Published
2026-05-14 13:00
Modified
2026-05-15 03:56
Severity ?
8.8 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CWE
  • CWE-242 - Use of Inherently Dangerous Function
Summary
Use of inherently dangerous function PQfn(..., result_is_int=0, ...) in PostgreSQL libpq lo_export(), lo_read(), lo_lseek64(), and lo_tell64() functions allows the server superuser to overwrite a client stack buffer with an arbitrarily-large response. Like gets(), PQfn(..., result_is_int=0, ...) stores arbitrary-length, server-determined data into a buffer of unspecified size. Because both the \lo_export command in psql and pg_dump call lo_read(), the server superuser can overwrite pg_dump or psql stack memory. Versions before PostgreSQL 18.4, 17.10, 16.14, 15.18, and 14.23 are affected.
References
Impacted products
Vendor Product Version
n/a PostgreSQL Version: 18   < 18.4
Version: 17   < 17.10
Version: 16   < 16.14
Version: 15   < 15.18
Version: 0   < 14.23
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        "metrics": [
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            "other": {
              "content": {
                "id": "CVE-2026-6477",
                "options": [
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                    "Exploitation": "none"
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                    "Automatable": "no"
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                  {
                    "Technical Impact": "total"
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                "role": "CISA Coordinator",
                "timestamp": "2026-05-14T00:00:00+00:00",
                "version": "2.0.3"
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          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
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          "vendor": "n/a",
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      "credits": [
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          "value": "The PostgreSQL project thanks Yu Kunpeng and Martin Heistermann for reporting this problem."
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          "value": "Use of inherently dangerous function PQfn(..., result_is_int=0, ...) in PostgreSQL libpq lo_export(), lo_read(), lo_lseek64(), and lo_tell64() functions allows the server superuser to overwrite a client stack buffer with an arbitrarily-large response.  Like gets(), PQfn(..., result_is_int=0, ...) stores arbitrary-length, server-determined data into a buffer of unspecified size.  Because both the \\lo_export command in psql and pg_dump call lo_read(), the server superuser can overwrite pg_dump or psql stack memory.  Versions before PostgreSQL 18.4, 17.10, 16.14, 15.18, and 14.23 are affected."
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          "url": "https://www.postgresql.org/support/security/CVE-2026-6477/"
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      "title": "PostgreSQL libpq lo_* functions let server superuser overwrite client stack memory",
      "workarounds": [
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          "lang": "en",
          "value": "use PQexecPrepared(), not PQfn(..., result_is_int=0, ...) or its lo_* wrappers"
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