Privileged server crash via recursive SIGHUP handling
Published Aug 22, 2023 · Updated Aug 4, 2024
Stack exhaustion in PostgreSQL 12.2 allows attackers with elevated privileges to crash the postmaster by repeatedly sending SIGHUP signals. The postmaster's signal setup fails to keep signals blocked throughout SIGHUP_handler execution, permitting rapid arrivals to invoke the handler recursively and exhaust the stack. PostgreSQL disputes the security classification because only a database superuser, a role granted pg_reload_conf, or a privileged operating-system account can trigger reloads; the demonstrated consequence is a server-process crash.
Summary
What happened
Stack exhaustion in PostgreSQL 12.2 allows attackers with elevated privileges to crash the postmaster by repeatedly sending SIGHUP signals. The postmaster's signal setup fails to keep signals blocked throughout SIGHUP_handler execution, permitting rapid arrivals to invoke the handler recursively and exhaust the stack. PostgreSQL disputes the security classification because only a database superuser, a role granted pg_reload_conf, or a privileged operating-system account can trigger reloads; the demonstrated consequence is a server-process crash.
The record
- CVE
- CVE-2020-21469
- Published
- Aug 22, 2023
- Updated
- Aug 4, 2024
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-120, T1499.004
- Attack vector
- local
- Privileges
- admin
Timeline
How it unfolded
- Aug 22, 2023CVE publishedPublication date reported by the CVE source.
- Aug 4, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Repeated-SIGHUP postmaster crash reproducerproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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