SB2026061750 - Red Hat Enterprise Linux 8 update for the postgresql:15 module
Published: June 17, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 4 vulnerabilities.
1) Link following (CVE-ID: CVE-2026-6475)
CWE-ID: CWE-59 - Improper Link Resolution Before File Access ('Link Following')
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to overwrite arbitrary local files.
The vulnerability exists due to symlink following in pg_basebackup plain format and pg_rewind when processing files from an origin server. A remote attacker can provide crafted symlinks to overwrite arbitrary local files.
User interaction is required to run pg_basebackup or pg_rewind. The attack has practical implications only if relevant action is taken before the server is started, such as moving files to a different VM or snapshotting the VM.
2) Stack-based buffer overflow (CVE-ID: CVE-2026-6477)
CWE-ID: CWE-121 - Stack-based buffer overflow
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber
The vulnerability allows a remote attacker to overwrite client stack memory.
The vulnerability exists due to a stack-based buffer overflow in libpq lo_* functions when processing an arbitrarily large server response through PQfn(..., result_is_int=0, ...). A remote attacker can induce a victim client to process a crafted server response to overwrite client stack memory.
User interaction is required to invoke affected client functionality such as psql \lo_export or pg_dump. The issue affects lo_export(), lo_read(), lo_lseek64(), and lo_tell64().
3) Information Exposure Through Timing Discrepancy (CVE-ID: CVE-2026-6478)
CWE-ID: CWE-208 - Information Exposure Through Timing Discrepancy
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to recover credentials sufficient to authenticate.
The vulnerability exists due to observable timing discrepancies in MD5-hashed password comparison during authentication. A remote attacker can measure authentication timing to recover credentials sufficient to authenticate.
The issue does not affect scram-sha-256 passwords and applies to MD5-hashed passwords that may originate from upgrades from PostgreSQL 13 or earlier.
4) Integer overflow (CVE-ID: CVE-2026-6473)
CWE-ID: CWE-190 - Integer overflow
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to integer overflow in multiple PostgreSQL server features when processing application-supplied input. A remote user can provide crafted input to cause a denial of service.
The integer wraparound can undersize an allocation and lead to an out-of-bounds write that results in a segmentation fault.
Remediation
Install update from vendor's website.