CVE-2021-40839
HIGHCVSS 7.5/10EPSS 5.43%
Last modified
CVE-2021-40839 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. The rencode package through 1.0.6 for Python allows an infinite loop in typecode decoding (such as via ;\x2f\x7f), enabling a remote attack that consumes CPU and memory.. EPSS estimates a 5.43% chance of exploitation in the next 30 days.
Description
The rencode package through 1.0.6 for Python allows an infinite loop in typecode decoding (such as via ;\x2f\x7f), enabling a remote attack that consumes CPU and memory.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Rencode Project | Rencode | <= 1.0.6 |
| Fedoraproject | Fedora | 34 |
| Fedoraproject | Fedora | 35 |
References
- https://github.com/aresch/rencode/commit/572ff74586d9b1daab904c6f7f7009ce0143bb75Patch, Third Party Advisory
- https://github.com/aresch/rencode/pull/29Patch, Third Party Advisory
- https://pypi.org/project/rencode/#historyThird Party Advisory
- https://seclists.org/fulldisclosure/2021/Sep/16Mailing List, Third Party Advisory
- https://security.netapp.com/advisory/ntap-20211008-0001/Third Party Advisory
- https://github.com/aresch/rencode/commit/572ff74586d9b1daab904c6f7f7009ce0143bb75Patch, Third Party Advisory
- https://github.com/aresch/rencode/pull/29Patch, Third Party Advisory
- https://pypi.org/project/rencode/#historyThird Party Advisory
- https://seclists.org/fulldisclosure/2021/Sep/16Mailing List, Third Party Advisory
- https://security.netapp.com/advisory/ntap-20211008-0001/Third Party Advisory
Timeline
- Published
- Last Modified
- Status
- Modified
Frequently Asked Questions
What is CVE-2021-40839?
The rencode package through 1.0.6 for Python allows an infinite loop in typecode decoding (such as via ;\x2f\x7f), enabling a remote attack that consumes CPU and memory.
How severe is CVE-2021-40839?
CVE-2021-40839 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 5.43% probability of exploitation in the next 30 days.
How do I fix CVE-2021-40839?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
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Are you affected by CVE-2021-40839?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST