Vulnerability Description
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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Postgresql | Postgresql | < 14.23 |
Related Weaknesses (CWE)
References
- https://www.postgresql.org/support/security/CVE-2026-6477/PatchVendor Advisory
FAQ
What is CVE-2026-6477?
CVE-2026-6477 is a vulnerability with a CVSS score of 8.8 (HIGH). 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 clie...
How severe is CVE-2026-6477?
CVE-2026-6477 has been rated HIGH with a CVSS base score of 8.8/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-6477?
Check the references section above for vendor advisories and patch information. Affected products include: Postgresql Postgresql.