CVE-2026-16240 (CVSS 3.7)

Description

Use of externally-controlled format string in PostgreSQL pg_basebackup allows an attacker having already compromised a server to achieve disclosure from pg_basebackup memory, via backup manifest bytes. The vulnerability does not return the improperly-read bytes back to the attacker's server, so a successful attack would need separate implementation-specific secrets for that. Integrity impact is unlikely; in particular, the applicable formatter does not support %n. Versions before PostgreSQL 18.7, 17.12, 16.16, 15.20, and 14.25 are affected.

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CVSS v3.1 Score

3.7

LOW

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

Weakness Type (CWE)

CWE-134 CWE-134

References

Other References

https://www.postgresql.org/support/security/CVE-2026-16240/

Frequently Asked Questions

What is CVE-2026-16240? +

Use of externally-controlled format string in PostgreSQL pg_basebackup allows an attacker having already compromised a server to achieve disclosure from pg_basebackup memory, via backup manifest bytes. The vulnerability does not return the improperly-read bytes back to the attacker's server, so a successful attack would need separate implementation-specific secrets for that. Integrity impact is unlikely; in particular, the applicable formatter does not support %n. Versions before PostgreSQL 18.7, 17.12, 16.16, 15.20, and 14.25 are affected. It has a CVSS v3.1 base score of 3.7 (LOW).

How severe is CVE-2026-16240? +

CVE-2026-16240 has a CVSS v3.1 score of 3.7 out of 10, rated LOW. This is a low-severity vulnerability with limited impact.

How do I check if I'm vulnerable to CVE-2026-16240? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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