Infinite loop in musl (Alpine package)

Published: 2020-11-21
Risk Medium
Patch available YES
Number of vulnerabilities 1
CVE ID CVE-2020-28928
Exploitation vector Network
Public exploit N/A
Vulnerable software
musl (Alpine package)
Operating systems & Components / Operating system package or component

Vendor Alpine Linux Development Team

Security Advisory

This security advisory describes one medium risk vulnerability.

1) Infinite loop

Risk: Medium

CVSSv3: 6.5 [CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C] [PCI]

CVE-ID: CVE-2020-28928

CWE-ID: CWE-835 - Loop with Unreachable Exit Condition ('Infinite Loop')

Exploit availability: No


The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to infinite loop within the wcsnrtombs() function in musl libc. A remote attacker can consume all available system resources and cause denial of service conditions.


Install update from vendor's website.

Vulnerable software versions

musl (Alpine package)

Alpine Linux 3.12

Alpine Linux 3.9
1.1.22-r4, 1.1.21-r1, 1.1.21-r2, 1.1.22-r0, 1.1.22-r1, 1.1.21-r0, 1.1.22-r3, 1.1.22-r2

Alpine Linux 3.6
1.1.17-r1, 1.1.17-r2, 1.1.18-r0, 1.1.18-r1, 1.1.18-r2, 1.1.17-r0, 1.1.18-r4, 1.1.18-r3

CPE External links

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.