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Review reviewHigh

CVE-2026-6477

PostgreSQL, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 10.0 Extended Update Support

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
8.8
EPSS
0.46%
37.2% percentile
CISA KEV
Not listed
Published
2026.05.14
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.46%
Technical severityCVSS 8.8

Vulnerability overview

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 product and versions

Product
PostgreSQL, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 10.0 Extended Update Support
Affected versions
>= 18 < 18.4, >= 17 < 17.10, >= 16 < 16.14, >= 15 < 15.18, < 14.23, >= 15.0 < 15.18, >= 16.0 < 16.14, >= 17.0 < 17.10, >= 18.0 < 18.4
Fixed versions
14.23, 15.18, 16.14, 17.10, 18.4

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that PostgreSQL, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 10.0 Extended Update Support and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CWE
CWE-120, CWE-242