What’s Vulnerable › Vulnerabilities

CVE-2021-40839

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 5.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-09-10 · updated 2026-06-17
• Weakness: CWE-835

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.

Affected products

• Fedoraproject Fedora: 34, 35
• Rencode Project Rencode: through 1.0.6

References

• https://github.com/aresch/rencode/commit/572ff74586d9b1daab904c6f7f7009ce0143bb75
• https://github.com/aresch/rencode/pull/29
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BMVQRPDVSVZNGGX57CFKCYT3DEYO4QB6/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MCLETLGVM5DBX6QNHQFW6TWGO5T3DENY/
• https://pypi.org/project/rencode/#history
• https://seclists.org/fulldisclosure/2021/Sep/16
• https://security.netapp.com/advisory/ntap-20211008-0001/
• https://github.com/aresch/rencode/commit/572ff74586d9b1daab904c6f7f7009ce0143bb75
• https://github.com/aresch/rencode/pull/29
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BMVQRPDVSVZNGGX57CFKCYT3DEYO4QB6/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MCLETLGVM5DBX6QNHQFW6TWGO5T3DENY/
• https://pypi.org/project/rencode/#history

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