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🛡️ CVE-2026-6477 — postgresql

🟠 CVSS 8.0 — High ✅ No Known Exploit CWE-242 OSV
8.0
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

PostgreSQL libpq lo_* functions let server superuser overwrite client stack memory

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 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.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: Required — someone has to click, open or visit something.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: High — total loss, or loss the attacker controls.

Weakness class

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

CVE-2026-6477 is recorded against 1 package.

  • postgresql

Timeline and source

Published on 18 May 2026 and last revised on 17 August 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from OSV.

References

nvd.nist.gov (Web)
www.postgresql.org (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
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access.redhat.com (Web)
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access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
bugzilla.redhat.com (Web)
security.access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)

Other advisories for this package

postgresql has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-242: Use of Inherently Dangerous Function) in other software:

CVE-2026-6477 on other distributions

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

Details

Severity HIGH
CVSS Score 8.0
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CWE CWE-242
Public Exploit ✅ No
Source OSV
Published 2026-05-18
Updated 2026-08-20
Modified 2026-08-17

Affected Packages

Software From version Fixed in
postgresql

References

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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