Summary
The libpq package provides the PostgreSQL client library, which allows client programs to connect to PostgreSQL servers.
Security Fix(es):
* postgresql: PostgreSQL: Operating system account hijack via symlink following in pg_basebackup and pg_rewind (CVE-2026-6475)
* postgresql: PostgreSQL libpq: Buffer overflow allows server superuser to overwrite client stack memory (CVE-2026-6477)
* postgresql: PostgreSQL: Credential recovery via covert timing channel in MD5 password comparison (CVE-2026-6478)
* postgresql: integer overflow can cause an undersized allocation and an out-of-bounds write (CVE-2026-6473)
For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.
Fixed packages 2
| Release | Package | Fixed in |
|---|---|---|
| AlmaLinux · 8 | libpq | 13.23-2.el8_10 |
| AlmaLinux · 8 | libpq-devel | 13.23-2.el8_10 |
Vulnerabilities 4
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High 8.8
PostgreSQL server undersizes allocations, via integer wraparound
Integer wraparound in multiple PostgreSQL server features allows an unprivileged database user to cause the server to undersize an allocation and write out-of-bounds. This may execute arbitrary code as the operating system user running the database. In applic…
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High 8.8CVE-2026-6475 Public exploit
PostgreSQL pg_basebackup and pg_rewind can overwrite unrelated files of origin superuser choice
Symlink following in PostgreSQL pg_basebackup plain format and in pg_rewind allows an origin superuser to overwrite local files, e.g. /var/lib/postgres/.bashrc, that hijack the operating system account. It will remain the case that starting the server after t…
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High 8.8
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 ge…
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Medium 6.5
PostgreSQL discloses MD5-hashed passwords via covert timing channel
Covert timing channel in comparison of MD5-hashed password in PostgreSQL authentication allows an attacker to recover user credentials sufficient to authenticate. This does not affect scram-sha-256 passwords, the default in all supported releases. However, cu…
References
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report
https://access.redhat.com/security/cve/CVE-2026-6473
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report
https://access.redhat.com/security/cve/CVE-2026-6475
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report
https://access.redhat.com/security/cve/CVE-2026-6477
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report
https://access.redhat.com/security/cve/CVE-2026-6478
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report
https://bugzilla.redhat.com/2477439
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report
https://bugzilla.redhat.com/2477442
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report
https://bugzilla.redhat.com/2477447
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report
https://bugzilla.redhat.com/2477448
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advisory
https://errata.almalinux.org/8/ALSA-2026-27738.html