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CVE-2026-6477

HIGHCVSS 8.8/10EPSS 0.45%

Last modified

CVE-2026-6477 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. 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. EPSS estimates a 0.45% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
8.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS Probability
0.45%

37.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
PostgresqlPostgresql< 14.23
PostgresqlPostgresql>= 15.0, < 15.18
PostgresqlPostgresql>= 16.0, < 16.14
PostgresqlPostgresql>= 17.0, < 17.10
PostgresqlPostgresql>= 18.0, < 18.4

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2026-6477?
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.
How severe is CVE-2026-6477?
CVE-2026-6477 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 0.45% probability of exploitation in the next 30 days.
How do I fix CVE-2026-6477?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST