Use After Free in GNU Cflow
CVE-2020-23856
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.
Vulnerability class: Use-After-Free
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.004 (33.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 34th percentile — 33.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
- GNU Cflow — versions 1.6
- Fedoraproject Fedora — versions 33, 34
Weakness classification (CWE)
References
- lists.gnu.org/archive/html/bug-cflow/2020-07/msg00000.html (Exploit, Mailing List, Vendor Advisory)
- github.com/yangjiageng/PoC/blob/master/PoC_cflow_uaf_parser_line1284 (Exploit, Third Party Advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
Frequently asked questions
- What is CVE-2020-23856?
- CVE-2020-23856 is a medium-severity vulnerability in GNU Cflow, classified under Use After Free. CVSS score: 5.5/10. Published 2021-05-18.
- How severe is CVE-2020-23856?
- Medium severity. CVSS v3 base score is 5.5 out of 10.