🛡️ CVE-2026-6477 on Debian — postgresql-13

⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

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.

Distribution advisory

This page covers CVE-2026-6477 as tracked by Debian, for the package postgresql-13. The fix is available in version 13.23-0+deb11u4; earlier versions remain affected.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. A user must be tricked into taking some action. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

Weakness class

DEBIAN-CVE-2026-6477 is classified as CWE-242: Use of Inherently Dangerous Function. The product calls a function that can never be guaranteed to work safely.

Affected software

DEBIAN-CVE-2026-6477 is recorded against 4 packages.

  • postgresql-13 (fixed in 13.23-0+deb11u4)
  • postgresql-15 (fixed in 15.18-0+deb12u1)
  • postgresql-17 (fixed in 17.10-0+deb13u1)
  • postgresql-18 (fixed in 18.4-1)

Timeline and source

Published on 14 May 2026 and last revised on 7 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

security-tracker.debian.org (Advisory)

CVE-2026-6477 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2026-05-14
Updated 2026-08-11
Modified 2026-08-07
Fix URL N/A

Affected Packages

Software From version Fixed in
postgresql-13 — 13.23-0+deb11u4
postgresql-15 — 15.18-0+deb12u1
postgresql-17 — 17.10-0+deb13u1
postgresql-18 — 18.4-1

Similar Threats

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