Bug Report: PostgreSQL 16 crashes on ALTER USER CURRENT_USER WITH PASSWORD

Summary

PostgreSQL server crashes with a segmentation fault when executing ALTER
USER CURRENT_USER WITH PASSWORD in PostgreSQL 16.10 and 16.11. The crash
results in immediate termination of the backend process and forces a full
instance restart.
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Affected Versions

-

PostgreSQL 16.10
-

PostgreSQL 16.11

Issue reproduced consistently on both versions.
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Environment

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OS: Linux (RHEL 9–compatible)
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Architecture: x86_64
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Build: Official PostgreSQL packages
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Authentication: SCRAM-SHA-256
-

Crash observed on primary instance (not hot standby)

(Exact OS/kernel/compiler details can be provided if required.)
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Steps to Reproduce

1.

Connect to PostgreSQL as a regular role (non-superuser):

psql -U test_user -d testdb

2.

Execute the following command:

ALTER USER CURRENT_USER WITH PASSWORD 'new_password';

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Expected Result

The password of the current user should be updated successfully, equivalent
to:

ALTER USER test_user WITH PASSWORD 'new_password';

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Actual Result

PostgreSQL backend process crashes with *SIGSEGV (signal 11)*.
The entire PostgreSQL instance is terminated and automatically restarted.
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Server Log Output

LOG: server process (PID 118262) was terminated by signal 11:
Segmentation fault
DETAIL: Failed process was running: ALTER USER CURRENT_USER WITH
PASSWORD 'xxxxxxxx'LOG: terminating any other active server
processesLOG: all server processes terminated; reinitializing

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Frequency

-

Reproducible 100% of the time
-

Occurs immediately upon execution of the statement

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Additional Notes

-

The issue *does not occur* when specifying the role name explicitly:

ALTER USER test_user WITH PASSWORD 'new_password';

-

The crash appears to be specifically related to the use of CURRENT_USER
as the role specification.

Impact

-

Any user executing this statement can crash the entire PostgreSQL
instance.
-

Presents a potential denial-of-service risk in multi-tenant environments.