CVE-2026-6477
HIGH8.8EPSS 0.05%PostgreSQL libpq lo_* functions let server superuser overwrite client stack memory
Published: 5/14/2026Modified: 5/25/2026
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.
Affected packages (9)
- Alpine/postgresql15from 0, < 15.18-r0
- Alpine/postgresql16from 0, < 16.14-r0
- Alpine/postgresql17from 0, < 17.10-r0
- Alpine/postgresql18from 0, < 18.4-r0
- Bitnami/postgresqlfrom 0, < 14.23.0, >= 15.0.0, < 15.18.0, >= 16.0.0, < 16.14.0, >= 17.0.0, < 17.10.0, >= 18.0.0, < 18.4.0
- Debian/postgresql-13from 0
- Debian/postgresql-15from 0, < 15.18-0+deb12u1
- Debian/postgresql-17from 0, < 17.10-0+deb13u1
- Debian/postgresql-18from 0, < 18.4-1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH8.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |