CVE-2020-23856

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-05-18 · updated 2026-06-17
Weakness: CWE-416

Description

Use-after-Free vulnerability in cflow 1.6 in the void call(char *name, int line) function at src/parser.c, which could cause a denial of service via the pointer variable caller->callee.

Affected products

Fedoraproject Fedora: 33, 34
GNU cflow: 1.6

References

https://github.com/yangjiageng/PoC/blob/master/PoC_cflow_uaf_parser_line1284
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BLSXGFK2NYPCJMPHSHE3W56ZU3ZO6RD7/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FZTTKZX274BVFZX7TMPEZG6UWL6UPMQF/
https://lists.gnu.org/archive/html/bug-cflow/2020-07/msg00000.html
https://github.com/yangjiageng/PoC/blob/master/PoC_cflow_uaf_parser_line1284
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BLSXGFK2NYPCJMPHSHE3W56ZU3ZO6RD7/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FZTTKZX274BVFZX7TMPEZG6UWL6UPMQF/
https://lists.gnu.org/archive/html/bug-cflow/2020-07/msg00000.html

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