CVE-2024-21502 is a high-severity (CVSS 7.5) CWE-457 vulnerability in fastecdsa. A fix is available for fastecdsa — see the affected versions and patch details below.
Uninitialized Variable in fastecdsa
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2024-21502.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
fastecdsaReal-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
Versions of the package fastecdsa before 2.3.2 are vulnerable to Use of Uninitialized Variable on the stack, via the curvemath_mul function in src/curveMath.c, due to being used and interpreted as user-defined type. Depending on the variable's actual value it could be arbitrary free(), arbitrary realloc(), null pointer dereference and other. Since the stack can be controlled by the attacker, the vulnerability could be used to corrupt allocator structure, leading to possible heap exploitation. The attacker could cause denial of service by exploiting this vulnerability.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | fastecdsa | all versions | 2.3.2pip install --upgrade 'fastecdsa==2.3.2' |
Affected Products
fastecdsaantonkueltzDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for fastecdsa, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update fastecdsa to 2.3.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-21502 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.
Frequently Asked Questions
Is CVE-2024-21502 in your dependencies?
Find it across PyPI, including transitive dependencies.