CVE-2020-23856
CVE-2020-23856 is a medium-severity vulnerability in Gnu Cflow with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-416.
Key facts
- Severity: Medium (CVSS 3.x base score 5.5)
- CVSS v2: 2.1
- EPSS exploit prediction: 0% (34th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-416
- Affected product: Gnu Cflow
- Published:
- Last modified:
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.
Frequently asked questions
- What is 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.
- How severe is CVE-2020-23856?
- CVE-2020-23856 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
- Is CVE-2020-23856 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (34th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2020-23856?
- CVE-2020-23856 primarily affects Gnu Cflow. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2020-23856?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- When was CVE-2020-23856 published?
- CVE-2020-23856 was published on 2021-05-18 and last updated on 2026-06-17.
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
Affected products (3)
- cpe:2.3:a:gnu:cflow:1.6:*:*:*:*:*:*:*
- cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
- cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
More vulnerabilities in Gnu Cflow
- CVE-2019-16166 — Medium (CVSS 6.5): GNU cflow through 1.6 has a heap-based buffer over-read in the nexttoken function in parser.c.
- CVE-2019-16165 — Medium (CVSS 6.5): GNU cflow through 1.6 has a use-after-free in the reference function in parser.c.
- CVE-2023-2789 — Low (CVSS 3.5): A vulnerability was found in GNU cflow 1.7. It has been rated as problematic. This issue affects the function…
All CVEs affecting Gnu Cflow →
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- CVE-2026-4688 — Critical (CVSS 10.0): Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability was fixed in Firefox…
- CVE-2025-24085 — Critical (CVSS 10.0): A use after free issue was addressed with improved memory management. This issue is fixed in iOS 18.3 and iPadOS 18.3,…
- CVE-2024-43102 — Critical (CVSS 10.0): Concurrent removals of certain anonymous shared memory mappings by using the UMTX_SHM_DESTROY sub-request of…
- CVE-2021-32495 — Critical (CVSS 10.0): Radare2 has a use-after-free vulnerability in pyc parser's get_none_object function. Attacker can read freed memory…