CVSS 3.1
3.7 lowCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:NCVE-2026-16240 PostgreSQL pg_basebackup can use backup manifest content as a format string
Low (3.7). EPSS 0.3% estimated probability of exploitation activity in the next 30 days.
On this page
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.
Severity
- EPSS
- 0.3% estimated probability of exploitation activity in the next 30 days; 19th percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
- CISA's assessment (SSVC)
- Exploitation: none · Automatable: no · Technical impact: partial, assessed 2026-11-12. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
- CWE
- CWE-134 Use of Externally-Controlled Format String
- Published
- Modified
- Assigned by
- PostgreSQL (CNA)
- NVD analysis
- Awaiting analysis
- Record from
- the NVD, synced
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Fix and patched versions
- Debian, Red Hat, Alpine: fixed package versions per release
Linux distributions
| Distribution | Release | Package | Fixed in | Advisory |
|---|---|---|---|---|
| Debian | 12 | postgresql-15 | no fix listed | DEBIAN-CVE-2026-16240 |
| Debian | 13 | postgresql-17 | 17.12-0+deb13u1 | DEBIAN-CVE-2026-16240 |
| Debian | 14 | postgresql-18 | no fix listed | DEBIAN-CVE-2026-16240 |
| Ubuntu | 20.04:LTS | postgresql-12 | no fix listed | UBUNTU-CVE-2026-16240 |
| Ubuntu | 22.04:LTS | postgresql-14 | no fix listed | UBUNTU-CVE-2026-16240 |
| Ubuntu | 24.04:LTS | postgresql-16 | no fix listed | UBUNTU-CVE-2026-16240 |
| Ubuntu | 26.04:LTS, 26.10 | postgresql-18 | no fix listed | UBUNTU-CVE-2026-16240 |
| Ubuntu | Pro:14.04:LTS | postgresql-9.3 | no fix listed | UBUNTU-CVE-2026-16240 |
| Ubuntu | Pro:16.04:LTS | postgresql-9.5 | no fix listed | UBUNTU-CVE-2026-16240 |
| Ubuntu | Pro:18.04:LTS | postgresql-10 | no fix listed | UBUNTU-CVE-2026-16240 |
| Red Hat | hummingbird:1 | libpq, libpq-devel | 0:18.7-0.1.hum1 | RHSA-2026:99821 |
| Alpine | v3.21, v3.22 | postgresql15 | 15.20-r0 | ALPINE-CVE-2026-16240 |
| Alpine | v3.21, v3.22, v3.23 and 1 more | postgresql16 | 16.16-r0 | ALPINE-CVE-2026-16240 |
| Alpine | v3.21, v3.22, v3.23 and 1 more | postgresql17 | 17.12-r0 | ALPINE-CVE-2026-16240 |
| Alpine | v3.23, v3.24 | postgresql18 | 18.7-r0 | ALPINE-CVE-2026-16240 |
| Azure Linux | 3 | postgresql | no fix listed | AZL-113795 |
From the distributions' data via OSV.dev: the Debian Security Tracker; Ubuntu Security Notices © Canonical Ltd., CC BY-SA 4.0; Red Hat Security Data © Red Hat, Inc., CC BY 4.0; the Alpine secdb, CC BY-SA 4.0; Microsoft's Azure Linux vulnerability data, MIT. Modified: reformatted and linked to CVE records. Credits. On the distributions' own pages: Debian · Ubuntu · Red Hat · Alpine.
Red Hat
Red Hat rates this Low.
This vulnerability is rated with a Low severity impact on Red Hat products because successful exploitation requires an adversary to have already gained control over the target database server before interacting with the client utility. The pg_basebackup tool is a short-lived administrative utility invoked on demand, significantly narrowing the window of exposure compared to continuously running services. Furthermore, memory contents are not automatically exfiltrated across the network during execution, and arbitrary memory write operations are precluded by the underlying formatting routine.
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Hardened Images | libpq | Affected | |
| Red Hat Hardened Images | postgresql17 | Affected | |
| Red Hat Hardened Images | postgresql18 | Affected |
Contains Red Hat Security Data © Red Hat, Inc., licensed under CC BY 4.0. Source: https://access.redhat.com/security/data. Modified: reformatted. Red Hat's page for CVE-2026-16240.
Attack patterns (CAPEC)
- CAPEC-67 String Format Overflow in syslog() Likelihood: High · Severity: Very High
- CAPEC-135 Format String Injection Likelihood: High · Severity: High
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.