CVE
PostgreSQL dblink and subscriptions can append to arbitrary files
Affects PostgreSQL 18 before 18.7 and older branches; older branches are also affected when libpq 18 or later is installed and used by the server. Fixed in 18.7, 17.12, 16.16, 15.20 and 14.25.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 18.7, 17.12, 16.16, 15.20, 14.25
- Who is exposed
- Specific setups only
Do first: Check whether your setup matches what the bug needs. Superuser previously granted pg_create_subscription to non-superuser roles. PostgreSQL 18.x minor versions before 18.7. Versions before PostgreSQL 18 when libpq version 18 or later is installed and in use by the server.
- Published
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 33/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: no
- Technical impact: partial
Summary
External control of file name in PostgreSQL dblink and CREATE/ALTER SUBSCRIPTION allows a user to achieve persistent denial of service, via appending invalid data to a chosen file. Specifically, the "sslkeylogfile" connection parameter appends data, in NSS keylog format, to a file of the user's choosing. This "sslkeylogfile" mechanism cannot add arbitrary bytes. Within major version 18, minor versions before PostgreSQL 18.7 are affected. Versions before PostgreSQL 18 are also affected if libpq version 18 or later is installed and in use by the server.
Who should check
Teams running PostgreSQL 18.x before 18.7, or older versions with libpq 18+ in use, that have the dblink extension or pg_create_subscription granted to non-superuser roles.
Read the source excerpt
“Within major version 18, minor versions before PostgreSQL 18.7 are affected.”
cve.now Index
- Exploitation0/40No signal
- Exposure8/25Specific setups only, reachable over the network
- Reach17/20Affects PostgreSQL (a widely deployed server, runtime, framework or database)
- Severity8.1/10CVSS 8.1
- No patch0/5No signal
What would change the score
- Would score about 83 if added to CISA KEV
- Would score about 78 if CISA's SSVC rates exploitation active
- Would score about 40 if CISA's SSVC rates it automatable
What to do
Check whether your setup matches what the bug needs.
Superuser previously granted pg_create_subscription to non-superuser roles. PostgreSQL 18.x minor versions before 18.7. Versions before PostgreSQL 18 when libpq version 18 or later is installed and in use by the server.Upgrade to a fixed version: 18.7, 17.12, 16.16, 15.20, 14.25.
Workaround: Revoke public EXECUTE permission on dblink functions, and revoke pg_create_subscription from roles that do not already have pg_write_server_files privileges.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-14661 (PostgreSQL dblink and subscriptions can append to arbitrary files), using the cve.now data below.
Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.
What cve.now has for CVE-2026-14661 (entry last updated 2026-11-12):
Affected:
- n/a PostgreSQL: from 18, fixed in 18.7; from 17, fixed in 17.12; from 16, fixed in 16.16; from 15, fixed in 15.20; fixed in 14.25
Fixed versions: 18.7, 17.12, 16.16, 15.20, 14.25.
Conditions (all must be true for the bug to be hit):
- Superuser previously granted pg_create_subscription to non-superuser roles. (source: https://www.cve.org/CVERecord?id=CVE-2026-14661)
- PostgreSQL 18.x minor versions before 18.7. (source: https://www.postgresql.org/support/security/CVE-2026-14661/)
- Versions before PostgreSQL 18 when libpq version 18 or later is installed and in use by the server. (source: https://www.postgresql.org/support/security/CVE-2026-14661/)
Setup: the bug needs a feature or setting that is off by default or uncommon. Check whether each asset has it on.
Attacker needs: network access, low-privilege login, no user action.
Workaround: Revoke public EXECUTE permission on dblink functions, and revoke pg_create_subscription from roles that do not already have pg_write_server_files privileges. (source: https://www.postgresql.org/support/security/CVE-2026-14661/)
CISA KEV: CVE-2026-14661 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-14661 only. If you also check another CVE, look up its own KEV status; never assume it from this one.
How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.
Verify against the linked advisories before concluding, and cite the date you read each one:
- https://www.postgresql.org/support/security/CVE-2026-14661/
- https://www.cve.org/CVERecord?id=CVE-2026-14661
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.
Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.
Entry: https://cve.now/CVE-2026-14661
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-14661"}.Timeline
- CVE published
- First seen by cve.now
- Posted on X by cve.now
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: partial
- Record last updated
Affected versions
- n/a PostgreSQL
From 18 · fixed in 18.7; From 17 · fixed in 17.12; From 16 · fixed in 16.16; From 15 · fixed in 15.20; fixed in 14.25
Evidence 3
Vendor advisory · 1
Establishes: Affected and fixed versions.
- Link
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-14661
Is CVE-2026-14661 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
An attacker can cause a persistent denial of service by appending invalid data to a file of their choosing, using the sslkeylogfile connection parameter.Source: cve.org, postgresql.org
Which versions are affected by CVE-2026-14661?
PostgreSQL: from 18 before 18.7; from 17 before 17.12; from 16 before 16.16; from 15 before 15.20; before 14.25.Source: cve.now feed data
Am I affected, and how do I check?
PostgreSQL 18 releases before 18.7 are affected, and earlier major versions are affected when libpq version 18 or later is installed and used by the server. The advisory also describes a setup where a superuser has granted pg_create_subscription to non-superuser roles. Check the server version with SELECT version(); and review which roles hold pg_create_subscription.Source: cve.org, postgresql.org
How do I fix CVE-2026-14661?
Upgrade to the fixed release for your major version: 18.7, 17.12, 16.16, 15.20 or 14.25.Source: cve.org, postgresql.org